Targeting Aurora kinase A suppresses the growth of human oral squamous cell carcinoma cells in vitro and in vivo

Identification of novel tumor-associated antigens and evaluation of a panel of autoantibodies in detecting oral cancer

BACKGROUND

We aimed to identify tumor-associated antigen (TAA) biomarkers through bioinformatic analysis and experimental verification, and to evaluate a panel of autoantibodies against tumor-associated antigens (TAAbs) for the detection of oral cancer (OC).

METHODS

GEO and TCGA databases were used to screen significantly up-regulated genes related to OC, and protein-protein interaction (PPI) analysis and Cystoscope software were used to identify key genes. Enzyme-linked immunosorbent assay (ELISA) was used to detect the expression levels of autoantibodies in 173 OC patients and 173 normal controls, and binary logistic regression analysis was used to build a diagnostic model.

RESULTS

Using bioinformatics, we identified 10 key genes (AURKA, AURKB, CXCL8, CXCL10, COL1A1, FN1, FOXM1, MMP9, SPP1 and UBE2C) that were highly expressed in OC. Three autoantibodies (anti-AURKA, anti-CXCL10, anti-FOXM1) were proven to have diagnostic value for OC in the verification set and the validation set. The combined assessment of these three autoantibodies improved the diagnostic value for OC, with an area under the curve (AUC), sensitivity and specificity of 0.741(95%CI:0.690-0.793),58.4% and 80.4%, respectively. In addition, the combination of these three autoantibodies also had high diagnostic value for oral squamous cell carcinoma (OSCC), with an AUC, sensitivity and specificity of 0.731(95%CI:0.674,0.786), 53.8% and 82.1%, respectively.

CONCLUSIONS

Our study revealed that AURKA, CXCL10 and FOXM1 may be potential biomarkers and the panel of three autoantibodies (anti-AURKA, anti-CXCL10 and anti-FOXM1) had good diagnostic value for OC.

MicroRNA-1289 Functions as a Novel Tumor Suppressor in Oral Squamous Cell Carcinoma

Recently, numerous tumor-suppressive microRNAs (TS-miRs) have been identified in human malignancies. Here, we attempted to identify novel TS-miRs in oral squamous cell carcinoma (OSCC). First, we transfected human OSCC cells individually with 968 synthetic miRs mimicking human mature miRs individually, and the growth of these cells was evaluated using the WST-8 assay. Five miR mimics significantly reduced the cell growth rate by less than 30%, and the miR-1289 mimic had the most potent growth inhibitory effect among these miRs. Subsequently, we assessed the in vivo growth-inhibitory effects of miR-1289 using a mouse model. The administration of the miR-1289 mimic-atelocollagen complex significantly reduced the size of subcutaneously xenografted human OSCC tumors. Next, we investigated the expression of miR-1289 in OSCC tissues using reverse transcription-quantitative PCR. The expression level of miR-1289 was significantly lower in OSCC tissues than in the adjacent normal oral mucosa. Furthermore, 15 genes were identified as target genes of miR-1289 via microarray and Ingenuity Pathway Analysis (IPA) microRNA target filtering. Among these genes, the knockdown of magnesium transporter 1 (MAGT1) resulted in the most remarkable cell growth inhibition in human OSCC cells. These results suggested that miR-1289 functions as a novel TS-miR in OSCC and may be a useful therapeutic tool for patients with OSCC.

Regulating the regulator: a survey of mechanisms from transcription to translation controlling expression of mammalian cell cycle kinase Aurora A

Aurora Kinase A (AURKA) is a positive regulator of mitosis with a strict cell cycle-dependent expression pattern. Recently, novel oncogenic roles of AURKA have been uncovered that are independent of the kinase activity and act within multiple signalling pathways, including cell proliferation, survival and cancer stem cell phenotypes. For this, cellular abundance of AURKA protein is per se crucial and must be tightly fine-tuned. Indeed, AURKA is found overexpressed in different cancers, typically as a result of gene amplification or enhanced transcription. It has however become clear that impaired processing, decay and translation of AURKA mRNA can also offer the basis for altered AURKA levels. Accordingly, the involvement of gene expression mechanisms controlling AURKA expression in human diseases is increasingly recognized and calls for much more research. Here, we explore and create an integrated view of the molecular processes regulating AURKA expression at the level of transcription, post-transcription and translation, intercalating discussion on how impaired regulation underlies disease. Given that targeting AURKA levels might affect more functions compared to inhibiting the kinase activity, deeper understanding of its gene expression may aid the design of alternative and therapeutically more successful ways of suppressing the AURKA oncogene.

Aurora-a confers radioresistance in human hepatocellular carcinoma by activating NF-κB signaling pathway

BACKGROUND

Radiotherapy failure is a significant clinical challenge due to the development of resistance in the course of treatment. Therefore, it is necessary to further study the radiation resistance mechanism of HCC. In our early study, we have showed that the expression of Aurora-A mRNA was upregulated in HCC tissue samples or cells, and Aurora-A promoted the malignant phenotype of HCC cells. However, the effect of Aurora-A on the development of HCC radioresistance is not well known.

METHODS

In this study, colony formation assay, MTT assays, flow cytometry assays, RT-PCR assays, Western blot, and tumor xenografts experiments were used to identify Aurora-A promotes the radioresistance of HCC cells by decreasing IR-induced apoptosis in vitro and in vivo. Dual-luciferase reporter assay, MTT assays, flow cytometry assays, and Western blot assay were performed to show the interactions of Aurora-A and NF-κB.

RESULTS

We established radioresistance HCC cell lines (HepG2-R) and found that Aurora-A was significantly upregulated in those radioresistant HCC cells in comparison with their parental HCC cells. Knockdown of Aurora-A increased radiosensitivity of radioresistant HCC cells both in vivo and in vitro by enhancing irradiation-induced apoptosis, while upregulation of Aurora-A decreased radiosensitivity by reducing irradiation-induced apoptosis of parental cells. In addition, we have showed that Aurora-A could promote the expression of nuclear IkappaB-alpha (IκBα) protein while enhancing the activity of NF-kappaB (κB), thereby promoted expression of NF-κB pathway downstream effectors, including proteins (Mcl-1, Bcl-2, PARP, and caspase-3), all of which are associated with apoptosis.

CONCLUSIONS

Aurora-A reduces radiotherapy-induced apoptosis by activating NF-κB signaling, thereby contributing to HCC radioresistance. Our results provided the first evidence that Aurora-A was essential for radioresistance in HCC and targeting this molecular would be a potential strategy for radiosensitization in HCC.

Identification and evaluation of novel drug combinations of Aurora kinase inhibitor CCT137690 for enhanced efficacy in oral cancer cells

Oral cancer is the most prevalent subtype of head and neck cancers and arises mainly from squamous cells of the oral cavity. Patients with advanced metastatic disease have poor overall survival resulting primarily from limited treatment options. Recent advances in the understanding of molecular basis of oral tumorigenesis provide an opportunity for identification and validation of new drug targets. The deregulated expression of the Aurora family of mitotic kinases, for example, has been associated with pathogenesis and poor prognosis in oral cancer. Here, we have evaluated the efficacy of the pan-Aurora inhibitor (CCT137690) alone and in combination with different chemotherapeutic and targeted drugs to identify its synergistic partners in oral cancer cell lines (ORL-48 and ORL-115). CCT137690 effectively inhibits Aurora kinases in both the cell lines and displays potent antiproliferative activity towards them. Prolonged treatment of these cells with CCT137690 results in abrogated mitotic spindle formation, misaligned chromosome attachment and polyploidy that ultimately leads to apoptotic cell death. We further identified that inhibitors of EGFR (gefitinib) and PI3-kinase (pictilisib) synergize with CCT137690 to inhibit the proliferation of the oral cancer cell lines. Moreover, we demonstrate that polyethylene glycol-based nanocapsules harboring combinations of CCT137690 with gefitinib or pictilisib inhibit the growth of oral cancer cell lines in 3D spheroid cultures and induce apoptosis that is comparable to free drug combinations. In conclusion, we have demonstrated the in vitro efficacy of CCT137690 in oral cancer cell lines, identified novel drug combinations with CCT137690 and synthesized nanocapsules containing these drug combinations for co-administration.

Aurora-A affects radiosenstivity in cervical squamous cell carcinoma and predicts poor prognosis

BACKGROUND

Definitive radiation therapy (RT) (with or without cisplatin-based chemotherapy) is one of the most effective treatments for cervical squamous cell carcinoma (CSCC), but efficacy is limited due to resistance. In the present study, we investigated the relationship between the expression of Aurora kinase A (Aurora-A, AURKA)and response to RT in patients with CSCC.

METHODS

The expression of Aurora-A in biopsy specimens of untreated primary tumors in 129 Uyghur patients with CSCC was investigated immunohistochemically. Primary treatment in these patients was definitive radical RT, which consisted of pelvic RT plus brachytherapy (total point A dose:70-85 Gy) (with or without cisplatin-based chemotherapy). The prognostic value of tumoral Aurora-A expression and patients' clinical outcomes were evaluated.

RESULTS

Aurora-A expression was significantly associated with lymph node metastasis (P<0.001), large tumor size (P<0.001), low hemoglobin (Hb) level (P=0.011) and recurrence (P<0.001), but not other clinicopathological factors. Definitive RT was unfavorable in patients with high Aurora-A expression (P < 0.001). In 129 enrolled patients, lymph node metastasis, large tumor size, low Hb level, and AURKA overexpression were prognostic factors for both recurrent free survival (RFS) and overall survival (OS) in univariate analysis. However, only high AURKA expression was an adverse independent risk factor for both RFS (hazard ratio, 3.953; 95% CI, 1.473-10.638; P = 0.006) and OS (hazard ratio 9.091; 95%CI 2.597-32.258; P<0.001) in multivariate analyses.

CONCLUSIONS

Aurora-A may serve as a predictive biomarker of radiation response and a therapeutic target to reverse radiation therapy resistance.

Inhibition of Pro-inflammatory and Anti-apoptotic Biomarkers during Experimental Oral Cancer Chemoprevention by Dietary Black Raspberries

Oral cancer continues to be a significant public health problem worldwide. Recently conducted clinical trials demonstrate the ability of black raspberries (BRBs) to modulate biomarkers of molecular efficacy that supports a chemopreventive strategy against oral cancer. However, it is essential that a preclinical animal model of black raspberry (BRB) chemoprevention which recapitulates human oral carcinogenesis be developed, so that we can validate biomarkers and evaluate potential mechanisms of action. We therefore established the ability of BRBs to inhibit oral lesion formation in a carcinogen-induced rat oral cancer model and examined potential mechanisms. F344 rats were administered 4-nitroquinoline 1-oxide (4NQO) (20 µg/ml) in drinking water for 14 weeks followed by regular drinking water for 6 weeks. At week 14, rats were fed a diet containing either 5 or 10% BRB, or 0.4% ellagic acid (EA), a BRB phytochemical. Dietary administration of 5 and 10% BRB reduced oral lesion incidence and multiplicity by 39.3 and 28.6%, respectively. Histopathological analyses demonstrate the ability of BRBs and, to a lesser extent EA, to inhibit the progression of oral cancer. Oral lesion inhibition by BRBs was associated with a reduction in the mRNA expression of pro-inflammatory biomarkers Cxcl1, Mif, and Nfe2l2 as well as the anti-apoptotic and cell cycle associated markers Birc5, Aurka, Ccna1, and Ccna2. Cellular proliferation (Ki-67 staining) in tongue lesions was inhibited by BRBs and EA. Our study demonstrates that, in the rat 4NQO oral cancer model, dietary administration of BRBs inhibits oral carcinogenesis via inhibition of pro-inflammatory and anti-apoptotic pathways.

Predictive value of p63, ki-67, and survivin expression in oral leukoplakia: A tissue microarray study

The aim of this study was to analyze the immunohistochemical expression of survivin, ki-67, and p63 in oral leukoplakic lesions, histopathologically differentiated into dysplastic and nondysplastic. A tissue microarray containing 57 samples of biopsies from clinically classified lesions, such as leukoplakia, was immunolabeled for survivin, ki-67, and p63. Samples were scored for percentage of positively stained. Scores were designated as follows: low = less than 25% of positive cells; and high = more than 25% of positive cells. On performing histopathological diagnosis, 20 dysplastic lesions and 37 nondysplastic lesions were seen, in which female patients (56.1%) were predominant with an average age of 58.27 years. The study showed a high expression of 37.5% for survivin, 43.7% for ki-67, and 88.2% for p63 in dysplastic lesions. However, there was a high expression of 16.7% for survivin, 16.7% for ki-67, and 92% for p63 in nondysplastic lesions. There is a positive correlation of expression among the three antibodies. In the association of immunoreactivity, in both dysplastic and nondysplastic lesions, increased expression of survivin reflects on the increased expression of ki-67, and there is an overexpression of p63. In leukoplakia, the expression of survivin associated with that of ki-67 reinforces the assumption that all these lesions are potentially malignant, regardless of histopathology; and the overexpression of p63 may indicate carcinogenic potential. These findings may help in the treatment of patients with this type of lesion.

Therapeutic potential of targeting cell division cycle associated 5 for oral squamous cell carcinoma

Molecularly targeted drugs are used in the treatment of a variety of malignant tumors, but this approach to developing novel therapies for oral squamous cell carcinoma (OSCC) has lagged behind the progress seen for other cancers. We have attempted to find appropriate molecular targets for OSCC and identified cell division cycle associated 5 (CDCA5) as a cancer-related gene which was overexpressed in all the human OSCC cells tested by microarray analysis. In this study, we investigated the expression and function of CDCA5 in OSCC. First, we confirmed that CDCA5 was overexpressed in 4 human OSCC cell lines by quantitative RT-PCR and Western blotting. We then tested the effect of synthetic small interfering RNAs specific for CDCA5 on the growth and invasion of human OSCC cells. Knockdown of CDCA5 markedly inhibited the growth of OSCC cells in vitro and in vivo. We also examined the expression of CDCA5 protein in 80 cases of OSCC immunohistochemically and found a significant association between CDCA5 expression levels and overall survival. These results suggest that CDCA5 functions as a critical gene supporting OSCC progression and that targeting CDCA5 may be a useful therapeutic strategy for OSCC.

RNA interference in head and neck oncology

Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cause of cancer worldwide. The treatment of choice in case of head and neck cancer is surgery, followed by chemo- or/and radiotherapy. A potentially effective instrument to improve the outcome of numerous diseases, including viral infections, diabetes and cancer, is RNA interference (RNAi). It has been demonstrated that small interfering RNA and microRNA molecules are strongly involved in the regulation of various different pathological processes in cancer development. RNAi has become a valuable research tool allowing a better understanding of the mechanisms regulating cancer pathogenesis. Considering those advantages over other current therapeutics (including specificity and high efficacy), RNAi appears to be a potentially useful tool in cancer treatment. The present review discusses the current knowledge about the possibility of using RNAi in HNSCC therapy.

Aurora-A promotes chemoresistance in hepatocelluar carcinoma by targeting NF-kappaB/microRNA-21/PTEN signaling pathway

Hepatocellular carcinoma (HCC) is highly resistant to chemotherapy. Previously, we have shown that Aurora-A mRNA is upregulated in HCC cells or tissues and silencing of Aurora-A using small interfering RNA (siRNA) decreases growth and enhances apoptosis in HCC cells. However, the clinical significance of Aurora-A protein expression in HCC and association between Aurora-A expression and HCC chemoresistance is unclear. Here, we showed that Aurora-A protein is upregulated in HCC tissues and significantly correlated with recurrence-free and overall survival of patients and multivariate analysis indicated that immunostaining of Aurora-A will be an independent prognostic factor for patients. Silencing of Aurora-A significantly increased the chemosensitivity of HCC cells both in vitro and in vivo, while overexpression of Aurora-A induced the opposite effects. Furthermore, overexpression of Aurora-A reduces chemotherapy-induced apoptosis by promoting microRNA-21 expression, which negatively regulates PTEN and then inhibits caspase-3-mediated apoptosis induction. Mechanically, we demonstrated that Aurora-A promotes expression of nuclear Ikappaβ-alpha (Iκβα) protein and enhances NF-kappa B (NF-κB) activity, thus promotes the transcription of miR-21. This study first reported the involvement of Aurora-A/NF-κB/miR-21/PTEN/Akt signaling axis in chemoresistance of HCC cells, suggesting that targeting this signaling pathway would be helpful as a therapeutic strategy for the reversal of chemoresistance in HCC.

AURKA is a predictor of chemotherapy response and prognosis for patients with advanced oral squamous cell carcinoma

Increasing evidence proposes the benefits of cisplatin-based chemotherapy in a subpopulation of patients with oral squamous cell carcinoma (OSCC), yet reliable indicators for this subpopulation are poorly explored. AURKA, also known as aurora kinase A, playing important functions in cell mitosis and making cells resistant to cisplatin through dysregulation of DNA damage repair networks, has been reported to be upregulated in OSCC, making AURKA a promising indicator. In this study, we recruited 78 patients with advanced OSCC to examine the expression of AURKA and the correlation with chemotherapy response and clinical outcomes. We found that AURKA was strongly expressed in 31 (39.74 %) of the 78 advanced OSCC samples and its expression was significantly associated with cisplatin resistance (P = 0.023), clinical recurrence (P = 0.021), and 5-year survival (P = 0.019). Chemotherapy increased AURKA expression in post-chemotherapy samples, yet with no significance (P = 0.101). Multivariate Cox proportional hazards regression model analysis demonstrated that lymph node samples with positive, strong AURKA staining, and poor chemotherapy response were independently associated with the 5-year survival and disease-free survival. Inhibiting AURKA expression in OSCC cell lines remarkably increased their sensitivity to cisplatin treatment by 2.5-fold difference. Our results imply that the overexpression of AURKA in advanced OSCC not only plays a role in the disease course but also shows an involvement in cisplatin treatment response. AURKA level may be a valuable predictor for patients with advanced OSCC, with downregulation of AURKA being a promising adjuvant therapy in this patient population.

Expression profiling of metastatic renal cell carcinoma using gene set enrichment analysis

OBJECTIVE

To identify complex changes in cell biology occurring during metastatic progression of renal cell carcinoma using a novel gene expression analysis algorithm.

METHODS

Whole genome expression profiling was carried out on 32 snap-frozen samples of clear-cell renal cell carcinoma metastases, 29 primary tumors (14 low grade, 15 high grade) and 14 samples of normal kidney tissue using oligonucleotide microarrays. These data were analyzed with the gene set enrichment analysis method, which is able to detect even small, but significant, expression changes in functionally connected genes that cannot be shown by gene-by-gene comparisons.

RESULTS

There were 95 gene sets (pathways) with significant upregulation in metastases compared with normal kidney tissue (P < 0.01), and 77 gene sets with significant downregulation, respectively. Low-grade and high-grade tumors showed deregulation of various pathways that have previously not been described in renal cell carcinoma. There were significant changes of genes involved in cell cycle control, apoptosis, cell motility, metabolism, cell adhesion and cytoskeleton. Some promising new potential therapy targets were identified in renal cell carcinoma metastases; for example, aurora-kinase A and flap structure-specific endonuclease 1.

CONCLUSION

Expression profiling of metastatic renal cell carcinoma using the gene set enrichment analysis pathway analysis method provides new and detailed insights in alterations occurring in renal cell carcinoma during malignant transformation and progression. These data can help to develop new and specifically targeted renal cell carcinoma therapies.