Overexpression Of Aurora Kinase Research Articles

Aurora Kinases: Their Role in Cancer and Cellular Processes

Aurora kinases, belonging to a highly conserved family of serine/threonine kinases with critical roles in the regulation of the cell cycle, comprise three members: Aurora kinase A, B, and C, which serve as key mitotic regulators essential for maintaining chromosome stability. Aurora kinases play crucial roles in multiple events in mitotic such as the coordination of chromosomal and cytoskeletal events, regulation of the spindle assembly checkpoint pathway and cytokinesis to ensure the smooth progression of the cell cycle. Besides their mitotic functions, Aurora kinases are also involved in the regulation of meiosis. Gene amplification/mutation and overexpression of Aurora kinases have been detected in various solid and haematological cancers. In human tumours, Aurora kinases exhibit oncogenic roles associated with their mitotic roles, which drive the cancer cell proliferation and survival. Deregulation of Aurora kinase activity causes failure in centrosome function, spindle assembly, chromosomal alignment, and cytokinesis, eventually resulting in the mitotic abnormalities and genetic instability. These findings emphasize the crucial functions of Aurora kinases in cancer, prompting their recognition as valuable targets for cancer therapy. This review provides an overview of the structures and functions of Aurora kinases and sheds light on their oncogenic roles in cancer.

Identification of MYCN non-amplified neuroblastoma subgroups points towards molecular signatures for precision prognosis and therapy stratification.

Despite the extensive study of MYCN-amplified neuroblastomas, there is a significant unmet clinical need in MYCN non-amplified cases. In particular, the extent of heterogeneity within the MYCN non-amplified population is unknown. A total of 1566 samples from 16 datasets were identified in Gene Expression Omnibus (GEO) and ArrayExpress. Characterisation of the subtypes was analysed by ConsensusClusterPlus. Independent predictors for subgrouping were constructed from the single sample predictor based on the multiclassPairs package. Findings were verified using immunohistochemistry and CIBERSORTx analysis. We demonstrate that MYCN non-amplified neuroblastomas are heterogeneous and can be classified into 3 subgroups based on their transcriptional signatures. Within these groups, subgroup_2 has the worst prognosis and this group shows a 'MYCN' signature that is potentially induced by the overexpression of Aurora Kinase A (AURKA); whilst subgroup_3 is characterised by an 'inflamed' gene signature. The clinical implications of this subtype classification are significant, as each subtype demonstrates a unique prognosis and vulnerability to investigational therapies. A total of 420 genes were identified as independent subgroup predictors with average balanced accuracy of 0.93 and 0.84 for train and test datasets, respectively. We propose that transcriptional subtyping may enhance precision prognosis and therapy stratification for patients with MYCN non-amplified neuroblastomas.

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

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

Abstract 1416: Aurora kinase is synthetic lethal with APC loss of function in engineered human colon organoid models

Abstract Colorectal cancer (CRC) is the second most common cause of cancer-related deaths worldwide. The disease-initiating event in most CRC cases is the loss of function (LOF) of the adenomatous polyposis coli (APC) gene, accounting for 70-80% of CRC. Strategies to target cells that harbor the truncation mutation in APC, which leads to its LOF, may provide the opportunity to intercept tumorigenesis in CRC patients. High-risk CRC populations include patients with familial adenomatous polyposis (FAP), the inherited disorder caused by germline APC mutations. Aurora Kinase (AK), a family of serine/threonine kinases, is essential for proper cell division, and overexpression of AK has been associated with multiple heme and solid tumor malignancies, including CRC. Aurora kinases have been well-studied, both preclinically and clinically, as a target for therapeutic intervention across multiple cancers; however, the role of AK in CRC disease progression has not been fully explored. Here we report a synthetic lethal dependency between APC and AK which was identified in a human isogenic colon organoid model containing a genetically engineered APC LOF (APCLOF). Aurora A-specific, Aurora B-specific, and Pan-AK inhibitors were evaluated in isogenic APCLOF or APCWT colon organoids derived from multiple donors. All AK inhibitors demonstrated selective growth inhibition of the APCLOF organoid. The strongest synthetic lethal effect was observed with a pan-AK inhibitor showing greater than 1000-fold selectivity in the APCLOF colon organoids compared to APCWT. Interestingly, this activity diminished as oncogenic driver mutations in KRAS and/or p53 genes were introduced into the APCLOF organoids. These findings suggest that therapeutic benefit of AK inhibitors would be greater in early APCLOF driven adenomas as opposed to advanced CRC. Despite these encouraging results indicating therapeutic opportunity in early adenoma disease, on-target genotoxicity was observed in vitro through increases in micronuclei at pharmacologic doses. Therefore, although there is a high unmet need in FAP for therapeutic options, potential genotoxicity associated with AK inhibitor treatments may limit utility as an intervention strategy. Citation Format: Dana S. Gaffney, Eileen Vesely, David Pocalyko, Kurtis Bachman, Karla Wiehagen, Glenn Cowley, Victoria Wong, Prashanth Gokare, Peggy Guzzie-Peck, Sandy Weiner, Ann De Smedt, Jacqueline Kinyamu-Akunda, Tammy Bush, Zhuming Zhang, Robert Schulingkamp, Sylvia F. Boj, Rene Overmeer, Carla Verissimo, Roshni Nair. Aurora kinase is synthetic lethal with APC loss of function in engineered human colon organoid models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1416.

Activation of oxidative phosphorylation in TP53-inactive endometrial carcinomas with a poor prognosis

ObjectiveWe aimed to identify pathways for potential therapeutic targets by conducting molecular profiling of endometrial carcinomas in patients with poor prognosis.MethodsThe classification of endometrial carcinomas has undergone a paradigm shift...

The Relevance of Aurora Kinase Inhibition in Hematological Malignancies.

Aurora kinases are a family of serine/threonine protein kinases that play a central role in eukaryotic cell division. Overexpression of aurora kinases in cancer and their role as major regulators of the cell cycle quickly inspired the idea that their inhibition might be a potential pathway when treating oncologic patients. Over the past couple of decades, the search for designing and testing of molecules capable of inhibiting aurora activities fueled many pre-clinical and clinical studies. In this study, data from the past 10 years of in vitro and in vivo investigations, as well as clinical trials, utilizing aurora kinase inhibitors as therapeutics for hematological malignancies were compiled and discussed, aiming to highlight potential uses of these inhibitors as a novel monotherapy model or alongside conventional chemotherapies. While there is still much to be elucidated, it is clear that these kinases play a key role in oncogenesis, and their manageable toxicity and potentially synergistic effects still render them a focus of interest for future investigations in combinatorial clinical trials.

Direct Phosphorylation and Stabilization of MYC By Aurora B Kinase Promotes T Cell Leukemogenesis

The aberrant activation of oncogene MYC (also termed c-MYC) is one of the most common features in human cancer. The unleashed MYC oncogene frequently produces abundant MYC protein, which mediates a transcriptional response involved in a variety of biological processes, contributing to almost every aspect of tumorigenesis. The significance of MYC deregulation has been recognized in T-cell acute lymphoblastic leukemia (T-ALL), a life-threatening hematological malignancy with dismal outcome due to disease relapse and drug resistance. Therapeutic efforts aimed at inhibiting MYC expression or activity should have an important clinical relevance. However, attempts to directly disrupt MYC function have met with limited success, in part due to its "undruggable" protein structure. Aurora kinases, a multi-genic family of serine/threonine kinases, consist Aurora A (AURKA), Aurora B (AURKB) and Aurora C (AURKC). They are known to play an integral role in the regulation of cell division and chromosomal segregation. Amplification or overexpression of Aurora kinases is frequently found in human cancers with clear evidence of oncogenic potential, implicating Aurora kinases as rational anti-tumor targets. AURKB is the catalytic subunit of the chromosomal passenger protein complex (CPPC) which regulates multiple facets of cell division. Overexpression of AURKB has been reported in a variety of cancers and predicts poor overall survival. AZD1152 is a highly potent and selective inhibitor of Aurora B; preclinical evidence of anti-tumor efficacy with AZD1152 has extended to the clinical setting with tolerable toxicity. Despite considerable study, it remains largely unclear how expression of AURKB is elevated and, in particular, how elevated levels of AURKB reprogram cells to promote the cancer progression. We identified AURKB as a novel MYC binding partner using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. To assess the potential role of AURKB in regulating MYC, we inhibited AURKB in multiple T-ALL cell lines and found that MYC protein expression was diminished significantly. Notably, depletion of AURKB failed to downregulate MYC mRNA, suggesting a post-transcriptional regulation of the MYC protein. We then assessed MYC protein decay in the presence or absence of AURKB expression. Time course experiments revealed that knockdown of AURKB significantly shortened the half-life of endogenous MYC in T-ALL cells. Consistently, AURKB depletion resulted in significant downregulation of MYC-induced gene expression programs, corroborating an essential role of AURKB in sustaining MYC transcriptional activities. Regulation of MYC degradation by ubiquitin-proteasome system is dependent on MYC phosphorylation. Initiation of MYC turnover requires GSK3b-mediated phosphorylation of threonine 58 (p-T58). Time-course analysis showed that treatment with AZD1152 in T-ALL cells resulted in a notable increase in MYC p-T58. We performed in vitro kinase assays and found that MYC is phosphorylated directly by AURKB. This phosphorylation counteracted GSK3b-directed Thr58 phosphorylation and subsequent FBW7-mediated proteasomal degradation and enhanced the MYC protein stability. The AURKB mRNA and protein are generally more abundant in human T-ALL than normal thymocytes. We demonstrated that MYC, in concert with TAL1, directly binds to the AURKB promoter and activates its transcription, thus constituting a reciprocal regulation between MYC and AURKB. In order to clarify the biological significance of the AURKB-MYC circuit, we co-injected the one-cell-stage zebrafish embryos with the rag2:EGFP-Myc construct alone or together with rag2:AURKB followed by fluorescent microscopy analysis. Our results demonstrate that AURKB phosphorylation of MYC is functionally important for T cell leukemogenesis in vivo. Moreover, inhibition of AURKB elicits dramatic MYC degradation in association with robust apoptosis in wild type-FBW7 T-ALL cells, suggesting that FBW7 mutational status may serve as a genetic predictor of sensitivity to AURKB inhibitors. In this study, we unravel a non-mitotic role of AURKB in promoting MYC stabilization via direct MYC phosphorylation at an unconventional site. Our findings decipher a previously unsuspected mechanism involved in MYC deregulation and highlight disruption of the AURKB-MYC signaling circuit as a promising T-ALL therapeutic strategy. Disclosures No relevant conflicts of interest to declare.

Impact of Aurora kinase A and B expression on response to neoadjuvant chemotherapy and patient outcome in muscle-invasive bladder cancer (MIBC).

393 Background: Identification of robust biomarkers that predict likelihood of benefit from neoadjuvant chemotherapy (NAC) in patients with MIBC remains an unmet need. Previous studies have implicated tumor overexpression of aurora kinases A (AURKA) and B (AURKB) as a mechanism of chemo-resistance. Because overexpression of AURKA has also emerged as a potential biomarker for detection of high-risk urothelial carcinoma, we sought to characterize the expression of AURKA, AURKB with clinical outcomes in MIBC patients who received NAC and to test the hypothesis that tumor overexpression of AURKA and AURKB would predict for residual MIBC. Methods: 47 patients with MIBC who received NAC prior to cystectomy were retrospectively identified. Immunohistochemistry for AURKA and AURKB was performed on pre-treatment diagnostic transurethral resection of bladder tumors and matched cystectomy specimens. Logistic regression models were estimated to determine the impact of pre-NAC expression on pathologic staging at cystectomy. Receiver Operator Characteristic curves (ROC) were calculated to assess diagnostic predictive ability of AURKA and AURKB. AURKA and AURKB were assessed for association with relapse-free survival (RFS) and overall survival (OS) using Kaplan-Meier techniques and Cox proportional hazards models. Results: 22 of 47 [46.8%] patients had residual muscle-invasive (ypT2-4) urothelial carcinoma after NAC. Neither baseline tumor expression of AURKA (ROC = 0.54, p = 0.71) nor AURKB (ROC = 0.46, p = 0.98) predicted for ypT2-4 status. However, baseline expression of AURKA above the 75th percentile for this cohort, determined by the percentage of tumor cells positive, was associated with an inferior RFS, [HR = 3.79, [1.40, 10.26] p = 0.005] and OS, [HR = 5.84, [2.14, 15.98], p < 0.001]. Similar trends for worse survival outcomes were also observed for high AURKB levels. Conclusions: Although baseline tumor AURKA and AURKB expression did not predict for pathologic residual MIBC after NAC, high expression of AURKA and AURKB predicted for inferior RFS and OS. Further evaluation of AURKA and AURKB as potential biomarkers and therapeutic targets in MIBC is warranted.

Aurora kinases: novel anti-breast cancer targets

Abstract Aurora kinases regulate multiple steps of mitotic cell division in eukaryotic cells. Overexpression of aurora kinases has been observed in some tumor cells, which suggests that abnormalities in aurora kinases are closely related to tumorigenesis. In additon, aurora kinases are often amplified or overexpressed in breast cancer cells, leading to chromosomal segregation abnormalities and genomic disorder, and thereby activating oncogenic pathways. Novel Aurora A kinase inhibitors are currently being studied in multiple phase I and II studies. In this review, we describe the biological functions and mechanisms of aurora kinases in breast cancer cells and summarize the preclinical findings related to aurora kinases in breast cancer.

Hyperammonemic encephalopathy in patients with fibrolamellar hepatocellular carcinoma: a new physiopathological pathway

Background: Hyperammonemic encephalopathy (HE) may be a fatal condition usually associated to liver failure and portosystemic shunting [1]. Howerver, there are rare conditions that may lead to HE, such as fibrolamellar hepatocellular carcinoma (FHC) [2]. Awareness of the possibility of HE in patients with normal liver function is fundamental to timely diagnosis and treatment. We describe a new physiopathological pathway to HE in this clinical scenario that allowed adequate treatment and full clinical recovery of a patient that did not reposnd with standard medical approach. Methods: A young male with large FHC and peritoneal carcinomatosis that developed rapid onset HE. With usual treatment to this condition, hyppermmonemia aggravated with coma. A different physiopathological pathway to HE was suspected and investigated: overexpression of Aurora Kinase A, c-MYC and ornithine descaboxylase resulting in ornithine transcarboxylase dysfunction and urea cycle disorder. Adequate treatment was initiated. Results: With adequate treatment to urea cylce disorder ammonia blood levels decreased normal levels. Patient presented full clinical recovery. He was submitted to chemotherapy with sorafenib and GEMOX, and blood ammonia levels remained normal. After eight months hepatic tumors and peritoneal carcinomatosis are significantly reducing. Conclusion: We identified a new physiopathological pathway to HE in patients with large growing hepatic tumors. This allowed adequate treatment of this condition and complete clinical recovery.

Aurora kinase A (AURKA) interaction with Wnt and Ras-MAPK signalling pathways in colorectal cancer

Hyperactivation of Wnt and Ras-MAPK signalling are common events in development of colorectal adenomas. Further progression from adenoma-to-carcinoma is frequently associated with 20q gain and overexpression of Aurora kinase A (AURKA). Interestingly, AURKA has been shown to further enhance Wnt and Ras-MAPK signalling. However, the molecular details of these interactions in driving colorectal carcinogenesis remain poorly understood. Here we first performed differential expression analysis (DEA) of AURKA knockdown in two colorectal cancer (CRC) cell lines with 20q gain and AURKA overexpression. Next, using an exact algorithm, Heinz, we computed the largest connected protein-protein interaction (PPI) network module of significantly deregulated genes in the two CRC cell lines. The DEA and the Heinz analyses suggest 20 Wnt and Ras-MAPK signalling genes being deregulated by AURKA, whereof β-catenin and KRAS occurred in both cell lines. Finally, shortest path analysis over the PPI network revealed eight ‘connecting genes’ between AURKA and these Wnt and Ras-MAPK signalling genes, of which UBE2D1, DICER1, CDK6 and RACGAP1 occurred in both cell lines. This study, first, confirms that AURKA influences deregulation of Wnt and Ras-MAPK signalling genes, and second, suggests mechanisms in CRC cell lines describing these interactions.

Expression of aurora kinases: Predictor of tumor dissemination in uterine carcinosarcoma.

Uterine carcinosarcoma is a rare, aggressive, and biphasic tumor. It comprises carcinomatous and sarcomatous components, and mitosis-associated factors are thought to discriminate these two lesions. Aurora kinases are mitotic enzymes that are highly expressed in uterine malignancies. To identify the clinical significance of aurora kinase expression, we performed immunohistochemistry on tissue microarrays using cores selected from areas with typical carcinomatous and sarcomatous characteristics. A total of 24 samples were included, from patients at Seoul National University Hospital diagnosed with uterine carcinosarcoma, and who undergone a staging operation between 1997 and 2012. Patients' clinical and pathological data were analyzed, and expression patterns of aurora kinases were investigated. Aurora kinases A and B were dominantly expressed in the cytoplasm, and phospho-aurora kinases A and B were expressed in the nuclei. Phospho-aurora kinase A and aurora kinase B showed significantly higher expression in the carcinomatous component (P=0.012 and 0.008). High expression of phospho-aurora kinase A was associated with lymphatic metastasis such as positive pelvic lymph node and omental involvement (P=0.012 and 0.037). Overexpression of aurora kinase B was related to vascular invasion (P=0.011). High expression of both phospho-aurora kinase A and aurora kinase B was a prognostic factor for progression-free survival in uterine carcinosarcoma (P=0.049). In conclusion, expression of aurora kinases is associated with bidirectional tumor dissemination into the lymphatic and hematogenous pathways. In addition, high expression of phospho-aurora kinase A and aurora kinase B is a predictor of progression-free survival. Therefore, inhibitors of aurora kinases might be a prospective therapeutic options for uterine carcinosarcoma.

Aurora kinase A in gastrointestinal cancers: time to target.

Gastrointestinal (GI) cancers are a major cause of cancer-related deaths. During the last two decades, several studies have shown amplification and overexpression of Aurora kinase A (AURKA) in several GI malignancies. These studies demonstrated that AURKA not only plays a role in regulating cell cycle and mitosis, but also regulates a number of key oncogenic signaling pathways. Although AURKA inhibitors have moved to phase III clinical trials in lymphomas, there has been slower progress in GI cancers and solid tumors. Ongoing clinical trials testing AURKA inhibitors as a single agent or in combination with conventional chemotherapies are expected to provide important clinical information for targeting AURKA in GI cancers. It is, therefore, imperative to consider investigations of molecular determinants of response and resistance to this class of inhibitors. This will improve evaluation of the efficacy of these drugs and establish biomarker based strategies for enrollment into clinical trials, which hold the future direction for personalized cancer therapy. In this review, we will discuss the available data on AURKA in GI cancers. We will also summarize the major AURKA inhibitors that have been developed and tested in pre-clinical and clinical settings.

Aurora Kinases and Potential Medical Applications of Aurora Kinase Inhibitors: A Review.

Aurora kinases (AKs) represent a novel group of serine/threonine kinases. They were originally described in 1995 by David Glover in the course of studies of mutant alleles characterized with unusual spindle pole configuration in Drosophila melanogaster. Thus far, three AKs A, B, and C have been discovered in human healthy and neoplastic cells. Each one locates in different subcellular locations and they are all nuclear proteins. AKs are playing an essential role in mitotic events such as monitoring of the mitotic checkpoint, creation of bipolar mitotic spindle and alignment of centrosomes on it, also regulating centrosome separation, bio-orientation of chromosomes and cytokinesis. Any inactivation of them can have catastrophic consequences on mitotic events of spindle formation, alignment of centrosomes and cytokinesis, resulting in apoptosis. Overexpression of AKs has been detected in diverse solid and hematological cancers and has been linked with a dismal prognosis. After discovery and identification of the first aurora kinase inhibitor (AKI) ZM447439 as a potential drug for targeted therapy in cancer treatment, approximately 30 AKIs have been introduced in cancer treatment.

Myc Commands an Aurora Kinase – Sumoylation Circuit Required for B Cell Lymphoma Growth and Survival

▪Myc oncoproteins (c-Myc, N-Myc and L-Myc) are transcription factors that regulate cell growth, cell division and metabolism under physiologic conditions. Myc overexpression is a hallmark of Burkitt lymphoma (BL) harboring MYC/IG translocations, and is frequently present in many advanced cancers. Myc overexpression is associated with aggressive disease, which is in part due to the destruction of select targets by the ubiquitin-proteasome system, for example Skp2SCF-directed destruction of the Cdk inhibitior p27Kip1 (Keller et al., EMBO 2007, Old et al., Mol. Canc. Res. 2010). We have identified a related means of post-translational protein modification, SUMOylation, as a pathway activated by Myc. Consequently, Myc-driven human BL and manifest Eµ-Myc mouse lymphomas are characterized by a hyperSUMOylation phenotype. Targeting SUMOylation in such lymphomas by a genetic approach results in growth inhibition and blocks lymphoma maintenance in vitro and in vivo. We further found that the SUMO pathway is in particular required for intact transitioning of the G2-M cell cycle checkpoint and through mitosis. The use of pharmacologic SUMOylation inhibitors (SUMOi) accordingly resulted in cell cycle arrest, polyploidy and cell death (Hoellein et al., Blood 2014).In this current report we aimed to identify crucial players of the Myc-SUMOylation axis by applying a mass spectrometry approach that used purified SUMOylated proteins in a conditional Myc-inducible B cell model. Stable isotope labeling permitted quantitative analysis of protein SUMOylation in the Myc-on versus Myc-off state. This screen identified Aurora kinase A as a Myc-regulated target of SUMOylation. Aurora kinases are essential regulators of mitosis and cytokinesis that are indispensable for Myc-driven transformed cells, and inhibition of Aurora kinase function results in similar effects as blocking SUMOylation, namely G2-M arrest, impaired cytokinesis resulting in polyploidy, and apoptosis (den Hollander et al., Blood 2010). We confirmed Myc-specific SUMO modification of Aurora kinase A and B and found reduced SUMOylation of both kinases upon treatment with pharmacologic SUMOylation inhibitors or shRNA targeting the key SUMOylation enzymes. Overexpression of Aurora kinase A and B mutants harboring a mutated SUMOylation motif resulted in a phenotype reminiscent of pharmacological SUMOi. This phenotype is independent of the Aurora kinase function since the SUMO motif mutation does not impair kinase activity. Moreover, in a comprehensive screen for specific E3-ligases that regulate the SUMO modification of the Aurora kinases we identified several SUMO E3 ligases that are also Myc induced.In summary, we propose a Myc-Aurora-kinase-SUMOylation circuit where Myc activation allows the induction of Aurora kinase transcription as well as the transcription of critical SUMOylation pathway genes. This mechanism contributes to sufficient Aurora kinase SUMOylation allowing faithful cell cycle passage and cytokinesis. In lymphoma and possibly other Myc-dependent cancers this pathway represents a target for synthetic lethal drug applications. DisclosuresNo relevant conflicts of interest to declare.

A Phase I Study of the Aurora a Kinase Inhibitor Alisertib in Combination with 7+3 Induction Chemotherapy in Patients with Acute Myeloid Leukemia

The aurora kinases play an essential role in regulating mitosis and cell division. Over-expression of aurora kinases A and B has been associated with poor-risk features in acute myeloid leukemia (AML). Preclinical studies suggest that small molecule aurora kinase inhibitors have activity in AML cell lines. Alisertib (MLN8237), a novel Aurora-A kinase inhibitor, has been generally well tolerated in early clinical trials of hematological malignancies, including AML. This study sought to evaluate tolerability of alisertib combined with standard “7+3” induction chemotherapy for AML.In this phase I, 3+3 cohort dose-escalation study, alisertib was administered with standard 7+3 induction for newly diagnosed AML. Those with acute promyelocytic leukemia or with AML and core-binding factor alterations were excluded. All patients received 7+3 induction (continuous infusion cytarabine 200mg/m2 x 7 days and intravenous idarubicin 12mg/m2 x 3 days), after which on day 8, alisertib was administered twice daily (BID) for 7 days. Dose escalation occurred via three cohorts (10mg BID, 20mg BID, 30mg BID). All underwent a mid-induction bone marrow biopsy, following the course of alisertib, to assess for residual disease, which if present, was to be treated with 5+2 re-induction (cytarabine 200mg/m2 x 5 days, idarubicin 12mg/m2 x 2 days) without alisertib. Following induction, up to four cycles of consolidation were allowed, using cytarabine (3g/m2 BID days 1,3,5 for those aged <60 and 2g/m2 daily days 1-5 for those aged ≥60) followed by alisertib, according to dose cohort, on days 6-12. After consolidation, alisertib maintenance was initiated, at cohort dose level, for days 1-7 of 21 day cycles, to be continued for 12 months or until disease progression. Those eligible for stem cell transplant (SCT), following induction and/or consolidation courses, were removed from study for this purpose.Currently, 14 patients are enrolled on study (n=3, 10mg BID; n=7, 20mg BID; n=4, 30mg BID). The median age was 62 (range 43-75); 9 (64%) were male, and all but 3 were Caucasian. One patient (7%) had therapy-related AML and six (43%) had underlying myelodysplasia. FLT3 mutations were detected in 3 (21%), NPM1 mutations in 2 (14%), CEBPA mutations in 2 (14%), and IDH1/IDH2 mutations in 4 patients (28.4%). One patient in cohort 2 died of sepsis, deemed unrelated to study drug, prior to completion of the toxicity assessment period and was replaced. Five patients have gone on to SCT. All patients received induction, 7 patients have undergone first consolidation, 3 a second consolidation, 2 a third consolidation, 1 a fourth consolidation, and 1 patient has started maintenance therapy. Alisertib has been well tolerated. All patients have experienced expected grade 4 toxicities of anemia, thrombocytopenia, and febrile neutropenia seen during the induction phase of treatment. At initial dose of 10mg BID, no dose-limited toxicities (DLTs) were encountered. In the 20mg BID cohort, one DLT was encountered, of delayed thrombocytopenia (G4 at day 40). The final cohort, at 30mg BID, is currently accruing (4 of 6 enrolled). No other DLTs have been detected, and other toxicities on study will be presented. The maximum tolerated dose (MTD) will be established upon completion of this cohort. To date, 11 of 12 (92%) evaluable patients have achieved remission following induction (8 cases of CR and 3 of CRp). During the course of the study, one patient has experienced relapse, and none have died. Thirteen of 14 evaluable patients had an ablated mid-induction marrow biopsy, with the remaining patient showing 6% blasts in a 20% cellular marrow at mid-induction. None of the patients have undergone re-induction with 5+2 at mid-induction. We anticipate that the study will be fully enrolled and closed to further accrual by the time of presentation.Alisertib, a novel aurora A kinase inhibitor, appears to be well tolerated in conjunction with standard induction chemotherapy in newly diagnosed AML. Currently, 13 of 14 treated patients have demonstrated marrow ablation at the mid-induction point of therapy, and none have required re-induction with 5+2. Eleven of 12 evaluable patients have achieved remission following induction. These results suggest that alisertib is well-tolerated and may hold promise as a therapeutic agent in AML, when combined with induction chemotherapy. Ongoing efforts seek to define the MTD and establish appropriate dosing for phase II studies. DisclosuresFathi:Millennium: Research Funding; Seattle Genetics: Advisory Board, Advisory Board Other; Agios: Advisory Board, Advisory Board Other. Attar:Agios: Employment.

Effects of selective inhibitors of Aurora kinases on anaplastic thyroid carcinoma cell lines.

Aurora kinases are serine/threonine kinases that play an essential role in cell division. Their aberrant expression and/or function induce severe mitotic abnormalities, resulting in either cell death or aneuploidy. Overexpression of Aurora kinases is often found in several malignancies, among which is anaplastic thyroid carcinoma (ATC). We have previously demonstrated the in vitro efficacy of Aurora kinase inhibitors in restraining cell growth and survival of different ATC cell lines. In this study, we sought to establish which Aurora might represent the preferential drug target for ATC. To this end, the effects of two selective inhibitors of Aurora-A (MLN8237) and Aurora-B (AZD1152) on four human ATC cell lines (CAL-62, BHT-101, 8305C, and 8505C) were analysed. Both inhibitors reduced cell proliferation in a time- and dose-dependent manner, with IC50 ranges of 44.3-134.2 nM for MLN8237 and of 9.2-461.3 nM for AZD1152. Immunofluorescence experiments and time-lapse videomicroscopy yielded evidence that each inhibitor induced distinct mitotic phenotypes, but both of them prevented the completion of cytokinesis. As a result, poliploidy increased in all AZD1152-treated cells, and in two out of four cell lines treated with MLN8237. Apoptosis was induced in all the cells by MLN8237, and in BHT-101, 8305C, and 8505C by AZD1152, while CAL-62 exposed to AZD1152 died through necrosis after multiple rounds of endoreplication. Both inhibitors were capable of blocking anchorage-independent cell growth. In conclusion, we demonstrated that either Aurora-A or Aurora-B might represent therapeutic targets for the ATC treatment, but inhibition of Aurora-A appears more effective for suppressing ATC cell proliferation and for inducing the apoptotic pathway.

Silencing of Aurora kinase A by RNA interference inhibits tumor growth in human osteosarcoma cells by inducing apoptosis and G2/M cell cycle arrest

The overexpression of Aurora kinase A (AURKA), a member of serine/threonine kinase family, has been observed in various types of human cancers. However, the role of AURKA in osteosarcoma (OS), the most common type of primary malignancy arising from bone, has not been clarified. We used AURKA-specific lentivirus-delivered short hairpin RNA (shRNA) to significantly and sustainably silence the endogenous AURKA expression in human OS cells SAOS-2 and U2OS. We found that AURKA downregulation in OS cells prominently decreased colony formation ability in vitro and tumorigenesis ability in vivo. We further evaluated the effect of AURKA silence on cell viability by MTT assay, cell apoptosis and cell cycle by flow cytometer detection. The results showed that AURKA silence inhibited cell viability by inducing cell apoptosis and G2/M cell cycle arrest in OS cells. Taken together, our findings indicate that AURKA plays a crucial role on OS growth by inhibiting cell apoptosis and propelling cell cycle. Inhibition of AURKA by lentivirus-delivered specific shRNA showed the therapeutic potential in treatment of osteosarcoma.

CDKN1A-mediated responsiveness ofMLL-AF4-positive acute lymphoblastic leukemia to Aurora kinase-A inhibitors

Overexpression of Aurora kinases is largely observed in many cancers, including hematologic malignancies. In this study, we investigated the effects and molecular mechanisms of Aurora kinase inhibitors in acute lymphoblastic leukemia (ALL). Western blot analysis showed that both Aurora-A and Aurora-B are overexpressed in ALL cell lines and primary ALL cells. Both VE-465 and VX-680 effectively inhibited Aurora kinase activities in nine ALL cell lines, which exhibited different susceptibilities to the inhibitors. Cells sensitive to Aurora kinase inhibitors underwent apoptosis at an IC50 of ∼10-30 nM and displayed a phenotype of Aurora-A inhibition, whereas cells resistant to Aurora kinase inhibitors (with an IC50 more than 10 μM) accumulated polyploidy, which may have resulted from Aurora-B inhibition. Drug susceptibility of ALL cell lines was not correlated with the expression level or activation status of Aurora kinases. Interestingly, RS4;11 and MV4;11 cells, which contain the MLL-AF4 gene, were both sensitive to Aurora kinase-A inhibitors treatment. Complementary DNA (cDNA) microarray analysis suggested that CDKN1A might govern the drug responsiveness of ALL cell lines in a TP53-independent manner. Most importantly, primary ALL cells with MLL-AF4 and CDKN1A expression were sensitive to Aurora kinase inhibitors. Our study suggests CDKN1A could be a potential biomarker in determining the drug responsiveness of Aurora kinase inhibitors in ALL, particularly in MLL-AF4-positive patients.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature