Copy number increase of aurora kinase A in colorectal cancers: a correlation with tumor progression

Exploring Core Genes by Comparative Transcriptomics Analysis for Early Diagnosis, Prognosis, and Therapies of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers with a high mortality rate. Early diagnosis and therapies for CRC may reduce the mortality rate. However, so far, no researchers have yet investigated core genes (CGs) rigorously for early diagnosis, prognosis, and therapies of CRC. Therefore, an attempt was made in this study to explore CRC-related CGs for early diagnosis, prognosis, and therapies. At first, we identified 252 common differentially expressed genes (cDEGs) between CRC and control samples based on three gene-expression datasets. Then, we identified ten cDEGs (AURKA, TOP2A, CDK1, PTTG1, CDKN3, CDC20, MAD2L1, CKS2, MELK, and TPX2) as the CGs, highlighting their mechanisms in CRC progression. The enrichment analysis of CGs with GO terms and KEGG pathways revealed some crucial biological processes, molecular functions, and signaling pathways that are associated with CRC progression. The survival probability curves and box-plot analyses with the expressions of CGs in different stages of CRC indicated their strong prognostic performance from the earlier stage of the disease. Then, we detected CGs-guided seven candidate drugs (Manzamine A, Cardidigin, Staurosporine, Sitosterol, Benzo[a]pyrene, Nocardiopsis sp., and Riccardin D) by molecular docking. Finally, the binding stability of four top-ranked complexes (TPX2 vs. Manzamine A, CDC20 vs. Cardidigin, MELK vs. Staurosporine, and CDK1 vs. Riccardin D) was investigated by using 100 ns molecular dynamics simulation studies, and their stable performance was observed. Therefore, the output of this study may play a vital role in developing a proper treatment plan at the earlier stages of CRC.

Aurora kinase A inhibition induces synthetic lethality in SMAD4-deficient colorectal cancer cells via spindle assembly checkpoint activation

SMAD4 loss-of-function mutations have been frequently observed in colorectal cancer (CRC) and are recognized as a drug target for therapeutic exploitation. In this study, we performed a synthetic lethal drug screening with SMAD4-isogenic CRC cells and found that aurora kinase A (AURKA) inhibition is synthetic lethal with SMAD4 loss. Inhibition of AURKA selectively inhibited the growth of SMAD4^-/- CRC in vitro and in vivo. Mechanistically, SMAD4 negatively regulated AURKA level, resulting in the significant elevation of AURKA in SMAD4^-/- CRC cells. Inhibition of AURKA induced G₂/M cell cycle delay in SMAD4^+/+ CRC cells, but induced apoptosis in SMAD4^-/- CRC cells. We further observed that a high level of AURKA in SMAD4^-/- CRC cells led to abnormal mitotic spindles, leading to cellular aneuploidy. Moreover, SMAD4^-/- CRC cells expressed high levels of spindle assembly checkpoint (SAC) proteins, suggesting the hyperactivation of SAC. The silencing of key SAC proteins significantly rescued the AURKA inhibition-induced cell death in SMAD4^-/- cells, suggesting that SMAD4^-/- CRC cells are hyper-dependent on AURKA activity for mitotic exit and survival during SAC hyperactivation. This study presents a unique synthetic lethal interaction between SMAD4 and AURKA and suggests that AURKA could be a potential drug target in SMAD4-deficient CRC.

Disease Modeling on Tumor Organoids Implicates AURKA as a Therapeutic Target in Liver Metastatic Colorectal Cancer

BACKGROUND & AIMS

Patient-derived tumor organoids recapitulate the characteristics of colorectal cancer (CRC) and provide an ideal platform for preclinical evaluation of personalized treatment options. We aimed to model the acquisition of chemotolerance during first-line combination chemotherapy in metastatic CRC organoids.

METHODS

We performed next-generation sequencing to study the evolution of KRAS wild-type CRC organoids during adaptation to irinotecan-based chemotherapy combined with epidermal growth factor receptor (EGFR) inhibition. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 protein (Cas9)-editing showed the specific effect of KRAS^G12D acquisition in drug-tolerant organoids. Compound treatment strategies involving Aurora kinase A (AURKA) inhibition were assessed for their capability to induce apoptosis in a drug-persister background. Immunohistochemical detection of AURKA was performed on a patient-matched cohort of primary tumors and derived liver metastases.

RESULTS

Adaptation to combination chemotherapy was accompanied by transcriptomic rather than gene mutational alterations in CRC organoids. Drug-tolerant cells evaded apoptosis and up-regulated MYC (c-myelocytomatosis oncogene product)/E2F1 (E2 family transcription factor 1) and/or interferon-α-related gene expression. Introduction of KRAS^G12D further increased the resilience of drug-persister CRC organoids against combination therapy. AURKA inhibition restored an apoptotic response in drug-tolerant KRAS-wild-type organoids. In dual epidermal growth factor receptor (EGFR)- pathway blockade-primed CRC organoids expressing KRAS^G12D, AURKA inhibition augmented apoptosis in cases that had acquired increased c-MYC protein levels during chemotolerance development. In patient-matched CRC cohorts, AURKA expression was increased in primary tumors and derived liver metastases.

CONCLUSIONS

Our study emphasizes the potential of patient-derived CRC organoids in modeling chemotherapy tolerance ex vivo. The applied therapeutic strategy of dual EGFR pathway blockade in combination with AURKA inhibition may prove effective for second-line treatment of chemotolerant CRC liver metastases with acquired KRAS mutation and increased AURKA/c-MYC expression.

Knockdown of AURKA sensitizes the efficacy of radiation in human colorectal cancer

AIMS

Abnormally amplified expression of AURKA (aurora kinase A) is closely related to chemo-resistance in human colorectal cancer, lung cancer and leukemia. However, the biological role of AURKA in response to radio-sensitivity in human colorectal cancer is still unknown. Therefore, we evaluated the radio-sensitize ability of perturbation AURKA in human colorectal cancer.

MAIN METHODS

The knockdown effect of shAURKA was determined by western blot and qRT-PCR, respectively. Cell growth was determined by CCK-8 and clonogenic assay. Cell migration and metastasis was measured by wound healing assay and transwell invasive assay, respectively. Cell cycle and apoptosis was analyzed by flow cytometry. The alteration of down-stream targets was determined by western blot analysis.

KEY FINDINGS

We observed that high-level of AURKA expression is associated with poor prognosis in CRC patients receiving radiotherapy. Knockdown of AURKA significantly sensitizes the efficacy of radiation on the proliferation of HCT116 and HT-29 cells. The combination of AURKA inhibition and radiation could effectively suppress the ability of cell migration and metastasis, but also synergistically induce cellular apoptosis and arrest cell cycle at G2/M phase. Further studies demonstrated that knockdown AURKA markedly enhanced the efficacy of radiation through elevated PARP cleavage and induced AURKA-mediated pro-apoptosis factor BIM. Meanwhile, knockdown of AURKA in combination with radiation synergistically suppressed the regulator in blockage of G2/M phase, CDK2.

SIGNIFICANCE

Taken together, our results provide the evidence that targeted inhibition of AURKA could be a promising strategy for enhancing the efficacy of radiation for the treatment of human colorectal cancer.

Recombinant human bone morphogenetic protein-2 inhibits gastric cancer cell proliferation by inactivating Wnt signaling pathway via c-Myc with aurora kinases

The detailed molecular mechanisms and safety issues of recombinant human bone morphogenetic protein-2 (rhBMP-2) usage in bone graft substitution remain poorly understood. To investigate the molecular mechanisms underlying the function of rhBMP-2 in gastric cancer cells, we used microarrays to determine the gene expression patterns related to the effects of rhBMP-2. Based on a gene ontology analysis, several genes were upregulated during the regulation of the cell cycle and BMP signaling pathway. MYC was found to be significantly decreased along with its downstream target genes, the aurora kinases (AURKs), by rhBMP-2 in the network analysis. We further confirmed this finding with western blot data that rhBMP-2 inhibited c-Myc, AURKs, and β-catenin in SNU484 and SNU638 cells. An AURK inhibitor significantly decreased c-Myc expression in gastric cancer cells. Combination treatment with rhBMP-2 and AURK inhibitor resulted in significantly decreased c-Myc expression compared with gastric cancer cells treated with an rhBMP-2 or AURK inhibitor, respectively. Similar effects for decreased c-Myc expression were observed when we silenced β-catenin in gastric cancer cells. These results indicate that rhBMP-2 attenuated the growth of gastric cancer cells via the inactivation of β-catenin via c-Myc and AURKs. Therefore, our findings suggest that rhBMP-2 could be safely used with patients who undergo gastric or gastroesophageal cancer surgery.

Amplification and up-regulation of MIR30D was associated with disease progression of cervical squamous cell carcinomas

Background

Cervical squamous cell carcinoma (CSCC) is the most frequent type among cervical cancers. Although the altered miRNA miR-30d expression and the amplified chromosome locus of MIR30D, 8q24, have been reported in somatic cancers, the definitive functional impact of such region especially in CSCC remains under-investigated.

Methods

One hundred thirty-six cases of CSCC tissues and matched adjacent normal ovarian epithelial tissues were assessed in this study. FISH and qPCR were performed to detect the copy number and microRNA expression of MIR30D gene in the collected samples. In in-vitro study, proliferation of CSCC cells were analyzed using WST-1 assay and invasion abilities of CSCC cells were evaluated by transwell assay. In-vivo study using a model of nude mice bearing tumor was also performed.

Results

Copy number gains of MIR30D were detected in 22.8% (31 out of 136) of CSCC samples. Copy number of MIR30D was positively correlated with tumor progression. CSCCs with lymph node metastases (LNM) also showed more frequencies (36.4%) of MIR30D amplification than those without LNM (18.4%, p < 0.05). CSCCs with increased copy number of MIR30D also showed a positive correlation with miR-30d up-regulation. Inhibition of miR-30d in CSCC cells led to impaired tumor growth and migration.

Conclusions

Copy number amplifications of MIR30D gene and enhanced expression of miR-30d were positively correlated with tumor progression in CSCCs, indicating miR-30d might play an oncomiric role in the progression of CSCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3201-0) contains supplementary material, which is available to authorized users.

Aurora Kinase A Is a Prognostic Marker in Colorectal Adenocarcinoma

BACKGROUND

Aurora kinase A (AURKA), or STK15/BTAK, is a member of the serine/threonine kinase family and plays important roles in mitosis and chromosome stability. This study investigated the clinical significance of AURKA expression in colorectal cancer patients in Korea.

METHODS

AURKA protein expression was evaluated by immunohistochemistry in 151 patients with colorectal adenocarcinoma using tissue microarray blocks. We analyzed the relationship between clinicopathological characteristics and AURKA expression. In addition, the prognostic significance of various clinicopathological data for progression-free survival (PFS) was assessed. Also we evaluated copy number variations by array comparative genomic hybridization and AURKA gene amplification using fluorescence in situ hybridization in colorectal carcinoma tissues.

RESULTS

AURKA gene amplification was found more frequently in the 20q13.2-13.33 gain-positive group than the group with no significant gain on the AURKA-containing locus. AURKA protein expression was detected in 45% of the cases (68/151). Positive staining for AURKA was observed more often in male patients (p = .035) and distally located tumors (p = .021). PFS was shorter in patients with AURKA expression compared to those with low-level AURKA expression (p < .001). Univariate analysis revealed that AURKA expression (p = .001), age (p = .034), lymphatic invasion (p = .001), perineural invasion (p = .002), and TNM stage (p = .013) significantly affected PFS. In a multivariate analysis of PFS, a Cox proportional hazard model confirmed that AURKA expression was an independent and significant prognostic factor in colorectal adenocarcinoma (hazard ratio, 3.944; p < .001).

CONCLUSIONS

AURKA could serve as an independent factor to predict a poor prognosis in Korean colorectal adenocarcinoma patients.

Inhibition of Aurora B by CCT137690 sensitizes colorectal cells to radiotherapy

Colorectal cancer is the third most commonly diagnosed cancer worldwide. Although surgery remains the best treatment for this disease, adjuvant chemotherapy and radiotherapy are also very important in clinical practice. However, the notorious refractory lack of responses to radiochemotherapy greatly limits the application of radiochemotherapy in the context of colorectal cancer.There is a growing interest in the role that Aurora B may play in colorectal cancer cell survival as well as other cancer subtypes. In the current study, we sought to ascertain whether blocking of Aurora B signaling machinery by a small molecule inhibitor, CCT137690, could synergize radiation-induced colorectal cancer cell death. Results showed that CCT137690 increases the sensitivity of SW620 cells to radiation. Mechanistic studies revealed that Aurora B-Survivin pathway may be involved in this synergistic effect.Taken together, our results for the first time show that Aurora B inhibition and radiation exert a synergistic effect, resulting in enhanced colorectal cancer cell death. This synergistic effect is clinically relevant as lower doses of radiation could be used for cancer treatment, and could provide significant clinical benefits in terms of colorectal cancer management, while reducing unwanted side-effects.

Aurora kinase A (AURKA) expression in colorectal cancer liver metastasis is associated with poor prognosis

Background:

Five-year survival after resection of colorectal cancer liver metastasis (CRLCM) is <30%. We recently found that aurora kinase A (AURKA) drives 20q gain-associated tumour progression and is associated with disease recurrence. This study evaluates the prognostic value of AURKA expression in CRCLM of patients who underwent liver resection.

Methods:

Tissue microarrays (TMAs) were generated using formalin-fixed paraffin-embedded CRCLM and matched primary tumour from a multi-institutional cohort of patients with CRCLM who underwent liver resection between 1990 and 2010. Tissue microarrays were stained for AURKA using immunohistochemistry, and a hazard rate ratio (HRR) for the association between overall survival (OS) and nuclear AURKA expression in CRCLM was calculated. Results were validated by 500-fold cross-validation.

Results:

The expression of AURKA was evaluated in CRCLM of 343 patients. High AURKA expression was associated with poor OS (HRR 1.55, P<0.01), with a cross-validated average HRR of 1.57 (P=0.02). Average HRR was adjusted for the established prognostic clinicopathological variables in a multivariate analysis (average HRR 1.66; P=0.02). The expression of AURKA in CRCLM was correlated to its expression in corresponding primary tumour (P<0.01).

Conclusion:

The expression of AURKA protein is a molecular biomarker with prognostic value for patients with CRCLM, independent of established clinicopathological variables.

A genome-wide study of cytogenetic changes in colorectal cancer using SNP microarrays: opportunities for future personalized treatment

In colorectal cancer (CRC), chromosomal instability (CIN) is typically studied using comparative-genomic hybridization (CGH) arrays. We studied paired (tumor and surrounding healthy) fresh frozen tissue from 86 CRC patients using Illumina's Infinium-based SNP array. This method allowed us to study CIN in CRC, with simultaneous analysis of copy number (CN) and B-allele frequency (BAF)--a representation of allelic composition. These data helped us to detect mono-allelic and bi-allelic amplifications/deletion, copy neutral loss of heterozygosity, and levels of mosaicism for mixed cell populations, some of which can not be assessed with other methods that do not measure BAF. We identified associations between CN abnormalities and different CRC phenotypes (histological diagnosis, location, tumor grade, stage, MSI and presence of lymph node metastasis). We showed commonalities between regions of CN change observed in CRC and the regions reported in previous studies of other solid cancers (e.g. amplifications of 20q, 13q, 8q, 5p and deletions of 18q, 17p and 8p). From Therapeutic Target Database, we identified relevant drugs, targeted to the genes located in these regions with CN changes, approved or in trials for other cancers and common diseases. These drugs may be considered for future therapeutic trials in CRC, based on personalized cytogenetic diagnosis. We also found many regions, harboring genes, which are not currently targeted by any relevant drugs that may be considered for future drug discovery studies. Our study shows the application of high density SNP arrays for cytogenetic study in CRC and its potential utility for personalized treatment.

The aurora kinase A inhibitor MLN8237 enhances cisplatin-induced cell death in esophageal adenocarcinoma cells

Esophageal adenocarcinomas are poorly responsive to chemotherapeutics. This study aimed to determine the levels of Aurora kinase A (AURKA) and the therapeutic potential of MLN8237, an investigational AURKA inhibitor, alone and in combination with cisplatin. Using quantitative real-time PCR, we detected frequent AURKA gene amplification (15 of 34, 44%) and mRNA overexpression (37 of 44, 84%) in esophageal adenocarcinomas (P < 0.01). Immunohistochemical analysis showed overexpression of AURKA in more than two-thirds of esophageal adenocarcinoma tissue samples (92 of 132, 70%; P < 0.001). Using FLO-1, OE19, and OE33 esophageal adenocarinoma cell lines, with constitutive AURKA overexpression and mutant p53, we observed inhibition of colony formation with a single treatment of 0.5 μmol/L MLN8237 (P < 0.05). This effect was further enhanced in combination with 2.5 μmol/L cisplatin (P < 0.001). Twenty-four hours after treatment with the MLN8237 or MLN8237 and cisplatin, cell-cycle analyses showed a sharp increase in the percentage of polyploid cells (P < 0.001). This was followed by an increase in the percentage of cells in the sub-G(1) phase at 72 hours, concordant with the occurrence of cell death (P < 0.001). Western blot analysis showed higher induction of TAp73β, PUMA, NOXA, cleaved caspase-3, and cleaved PARP with the combined treatment, as compared with a single-agent treatment. Using xenograft models, we showed an enhanced antitumor role for the MLN8237 and cisplatin combination, as compared with single-agent treatments (P < 0.001). In conclusion, this study shows frequent overexpression of AURKA and suggests that MLN8237 could be an effective antitumor agent, which can be combined with cisplatin for a better therapeutic outcome in esophageal adenocarcinomas.

Relationship of increased aurora kinase A gene copy number, prognosis and response to chemotherapy in patients with metastatic colorectal cancer

BACKGROUND

Increased Aurora kinase A gene copy number (AURKA-CN) has been reported in metastatic colorectal cancer (mCRC), with unknown relationship to clinical outcome. We correlated increased AURKA-CN in mCRC tumours with KRAS mutation status, overall and progression-free survival (OS, PFS).

METHODS

Sixty-one mCRC tumours were analysed for AURKA-CN using q-PCR, and KRAS mutation status by direct sequencing. Expression of AURKA protein was analysed by immunohistochemistry. Cox-proportional hazard method, Kaplan-Meier curves and log-rank statistics were used to estimate and compare the hazard ratios and median survival between the groups.

RESULTS

In all, 68% of tumour exhibited high AURKA-CN, and 29% had a KRAS mutation, without correlation between the two. Patients with high AURKA-CN tumours had longer median OS (48.6 vs 18.8 months, P=0.01), with stronger trend among KRAS wild-type tumours (median OS not reached vs 18.8 months, P=0.003). Progression-free survival was longer on first-line or second-line chemotherapy among patients with KRAS wild-type and high vs low AURKA-CN (first: 17.6 vs 5.13 months, P=0.04; second: 10.4 vs 5.1 months, P=0.01). AURKA-CN level did not affect outcomes among patients with KRAS mutant tumours.

CONCLUSION

Increased AURKA-CN is common in mCRC tumours and is associated with longer OS and longer PFS during chemotherapy, particularly in KRAS wild-type tumours.

Matrix metalloproteinase 2 promotes cell growth and invasion in colorectal cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related death in the western world. In this study, we evaluated the expression of matrix metalloproteinase 2 gene (MMP2) in CRC and analyzed its correlation with clinicopathological features. We found that the expression of MMP2 was significantly higher in CRC tissues than in the colorectal tissues. In addition, high levels of MMP2 protein were positively correlated with the status of tumor size, lymph node metastasis, distant metastasis, Dukes' stage, and tumor invasion. Moreover, patients with higher MMP2 levels had markedly shorter overall survivals than those with low MMP2 levels. Multivariate analysis results suggested that the level of MMP2 expression is an independent prognostic indicator for the survival of patients with CRC. Silencing MMP2 expression in CRC cell lines with lentiviral-mediated shRNA markedly suppressed cell proliferation, colony formation, and invasion. Furthermore, we observed that vascular endothelial growth factor (VEGF) and membrane type 1 (MT1)-MMP protein levels were decreased in MMP2-down-regulated colorectal cells. Therefore, our study demonstrated that MMP2 is an important factor related to carcinogenesis and metastasis of CRC, and MMP2 promotes CRC cell growth and invasion by up-regulating VEGF and MT1-MMP expression, which makes this pathway a potential target for cancer treatment.