Xiang Bo Wan

Aurora-A, a Negative Prognostic Marker, Increases Migration and Decreases Radiosensitivity in Cancer Cells

Centrosomal Aurora-A (Aur-A) kinase ensures proper spindle assembly and accurate chromosome segregation in mitosis. Overexpression of Aur-A leads to centrosome amplification, aberrant spindle, and consequent genetic instability. In the present study, Aur-A was found to be overexpressed in laryngeal squamous cell carcinoma (LSCC). Moreover, Aur-A expression was adversely correlated with median survival, and further identified as a potential independent factor for disease prognosis. Suppression of Aurora kinase activity chemically or genetically led to LSCC Hep2 cell cycle arrest and apoptotic cell death. Importantly, we found that Aur-A increases cell migration and this novel function was correlated with Akt1 activation. The enhanced cell migration induced by Aur-A overexpression could be abrogated by either small-molecule Akt1 inhibitor or short interfering RNA. VX-680, a selective Aurora kinase inhibitor, decreased Akt1 phosphorylation at Ser(473) and inhibited cell migration, but failed to do so in constitutive active Akt1 (myr-Akt1)-overexpressed cells. Moreover, our data suggested that overexpression of Aur-A kinase might also contribute to radioresistance of LSCC. Inhibiting Aur-A by VX-680 induced expression of p53 and potently sensitized cells to radiotherapy, leading to significant cell death. Ectopic overexpression of Aur-A, however, reduced p53 level and rendered cells more resistant to irradiation. Taken together, we showed that Aur-A kinase, a negative prognostic marker, promotes migration and reduces radiosensitivity in laryngeal cancer cells.

Elevated Beclin 1 expression is correlated with HIF-1α in predicting poor prognosis of nasopharyngeal carcinoma

Recent studies have suggested that autophagy plays a pivotal role in regulation of cancer development and progression. High expression of the autophagy-related Beclin 1 protein predicted favorable patient outcome in several tumors. Here, a randomized controlled trial (RCT)-derived 128 nasopharyngeal carcinoma (NPC) patients were subjected to analysis of Beclin 1 expression and survival probability. In this RCT, 61 patients treated with induction chemotherapy plus concurrent chemoradiotherapy were used as a training set to generate a Beclin 1 cutoff score for patient outcome by receiver operating characteristic (ROC) curve analysis. For validation, the ROC-derived cutoff point was subjected to analysis of the association of Beclin 1 expression with patient outcome and clinical characteristics in testing set. The testing set comprised of 67 patients received induction chemotherapy plus radiotherapy. In the testing set and overall patients, our univariate and multivariate analysis showed that higher Beclin 1 expression, defined by the training set ROC analysis-generated cutoff score, predicted poorer overall survival, progression-free survival and distant metastasis-free survival. However, we failed to detect a correlation between Beclin 1 and local failure-free survival. Moreover, a positive relationship between Beclin 1 and HIF-1α expression was found. Importantly, among patients with elevated HIF-1α expression, a subset with lower Beclin 1 expression displayed a significant overall survival advantage than those with higher expression (p = 0.036). Contrary to previous studies, our results demonstrated that high autophagic Beclin 1 expression was an inferior prognostic marker for NPC. HIF-1α-associated Beclin 1 high expression might facilitate NPC cells surviving from chemoradiotherapy, suggesting a novel therapeutic molecular target for NPC.

Endoscopic nasopharyngectomy for locally recurrent nasopharyngeal carcinoma.

Nasopharyngectomy is the primary treatment for locally recurrent nasopharyngeal carcinoma (rNPC). However, oncological nasopharyngectomy is difficult to achieve, even using extranasal surgical approaches, with potential risks of severe functional disabilities and serious complications. This report introduces an innovative, minimally invasive, oncological, endoscopic nasopharyngectomy.

Inhibition of Aurora-A suppresses epithelial-mesenchymal transition and invasion by downregulating MAPK in nasopharyngeal carcinoma cells

Mitotic serine/threonine kinase Aurora-A (Aur-A) plays a critical role in regulating centrosome segregation and spindle assemble. Aur-A overexpression causes excessive centrosome duplication and abnormal spindle structure, leading to tumor malignant progression. Here, we investigated Aur-A expression in nasopharyngeal carcinoma (NPC) and the association between Aur-A and NPC invasiveness. We showed that overexpression of Aur-A in tumor tissues was correlated with cranial bone invasion and clinical stage in NPC patients. Suppression of Aur-A by either selective Aurora inhibitory VX-680 or small-interfering RNA caused G(2)/M arrest and apoptotic cell death in NPC CNE-2 cells. Significantly, inhibition of Aur-A suppressed CNE-2 cell invasion and restored membrane expression of epithelial markers, E-cadherin and beta-catenin, suggesting a reversed epithelial-mesenchymal transition process in cancer cells. In addition, we found that Aur-A-regulated epithelial-mesenchymal transition and invasion were mediated by mitogen-activated protein kinase (MAPK) phosphorylation. Moreover, suppression of MAP kinase by small-interfering RNA or its upstream MEK1/2-selective inhibitor U0126 abrogated cell invasion enhanced by Aur-A overexpression. On the other hand, forced overexpression of constitutively active form of MEK1/2, MEK2DD, in CNE-2 cancer cells rescued cell invasive ability suppressed by VX-680-imposed Aur-A inhibition. Our results indicated that Aur-A acted through a downstream MAP kinase pathway to promote epithelial-mesenchymal transition and invasiveness in nasopharyngeal tumorigenesis. Small chemical inhibitor VX-680 may offer as a promising molecular targeting agent in human NPC.

High pretreatment serum lactate dehydrogenase level correlates with disease relapse and predicts an inferior outcome in locally advanced nasopharyngeal carcinoma.

PURPOSE Here, we evaluate the prognostic effect of pretreatment serum lactate dehydrogenase (LDH) in locally advanced nasopharyngeal carcinoma (NPC). METHODS AND MATERIALS Pretreatment serum samples from a randomized controlled trial, which contained 199 neoadjuvant chemoradiotherapy patients and 201 neoadjuvant-concurrent chemoradiotherapy cases with locally advanced NPC, were collected and examined for LDH. With 5-year follow-up, the prognostic effect of pretreatment serum LDH was analysed by Kaplan-Meier analysis and multivariate Cox regression model. RESULTS Three hundred and sixty-seven patients (91.75%) had a normal (109.0-245.0 U/L) pretreatment LDH level, compared to 33 cases (8.25%) that had a higher (≥245.0 U/L) LDH level. The mean and median pretreatment LDH levels of these 400 patients were 186.6 and 174.0 U/L (range, 83.0-751.0 U/L), respectively. Compared with the normal subset, elevated LDH level predicted an inferior 5-year overall survival (56.9% versus 76.8%, P=0.004), disease-free survival (DFS, 45.4% versus 64.7%, P=0.001), local relapse-free survival (76.1% versus 89.6%, P=0.019) and distant metastasis-free survival (DMFS, 54.3% versus 72.2%, P=0.001). Multivariate analysis confirmed that the LDH level was an independent prognostic factor to predict death, disease progression, local relapse and distant metastasis. For the subgroup with normal LDH (median point of 177.0 U/L), we detected an evident 5-year DFS (68.8% versus 59.5%, P=0.047) and DMFS advantage (77.3% versus 65.3%, P=0.016) in 109.0-177.0 U/L subset than that of 178.0-245.0 U/L subgroup. CONCLUSIONS Serological LDH level was an independent prognostic factor for locally advanced NPC. Combining pretreatment LDH with TNM staging might lead to more accurate risk definition.

Snail promotes lymph node metastasis and Twist enhances tumor deposit formation through epithelial-mesenchymal transition in colorectal cancer

Snail and Twist, transcriptional repressors of E-cadherin as well as inducers of epithelial-mesenchymal transition, play pivotal roles in tumor invasion and metastasis. We investigated the expression of Snail, Twist, and E-cadherin by immunohistochemistry in 193 colorectal cancers, including 79 with positive lymph nodes, 36 with tumor deposits, 39 with both, and 39 with no metastases. Snail was expressed to a greater extent in the group with positive lymph nodes (68.4%), whereas Twist was overexpressed in patients with other metastases (75.0%). Ectopic expression of Snail and Twist correlated with reduced membranous expression of E-cadherin. Importantly, Snail overexpression correlated significantly with lymph node metastasis (P < .0001), whereas Twist up-regulation correlated strongly with other metastases (P < .0001). Multivariate logistic regression analysis showed that Snail was an independent predictor of lymph node metastasis (odds ratio, 4.445; 95% confidence interval, 2.250-8.781; P < .0001), whereas Twist displayed predictive value for metastasis formation (odds ratio, 5.606; 95% confidence interval, 2.829-11.111; P < .0001), suggesting that lymph node and other metastases may follow different signaling pathways. In conclusion, ectopic expression of Snail and Twist contributed to lymph node and disseminated metastasis, respectively, by reducing E-cadherin expression, providing a novel role for Snail and Twist in the progression of colorectal cancer.

Low expression of Beclin 1, associated with high Bcl-xL, predicts a malignant phenotype and poor prognosis of gastric cancer.

Recent studies have suggested that dysregulation of autophagy plays a pivotal role in tumorigenesis. Here, we determined the prognostic value of autophagy-related protein Beclin 1 in gastric cancer. A total of 153 primary gastric cancer patients were subjected to analysis of Beclin 1 expression and survival prognosis. Among them, 68 patients were assigned randomly and used as a training set to generate a cutoff score for Beclin 1 expression by receive operating characteristic (ROC) curve analysis. The ROC-generated cutoff score was subjected to analyze the association of Beclin 1 with clinical characteristics and patient outcome. In a testing set (n = 85) and overall patients (n = 153), both univariate and multivariate analysis found that low expression of Beclin 1 predicted adverse overall survival and progression-free survival for gastric cancer patients. Furthermore, in each stage of gastric cancer patients, Beclin 1 expression was a prognostic indicator in patients with stage II, III and IV. Importantly, a reverse relationship between Beclin 1 and Bcl-xL expression was demonstrated. In patients of elevated Bcl-xL expression, a subset with lower Beclin 1 expression displayed an inferior overall survival and progression-free survival than those with higher Beclin 1 expression. Thus, our data demonstrated that low expression of Beclin 1, associated with high Bcl-xL, played as an independent biomarker, contributing to a more aggressive cancer cell phenotype and poor prognosis for gastric tumor.

IKKα restoration via EZH2 suppression induces nasopharyngeal carcinoma differentiation

Lack of cellular differentiation is a key feature of nasopharyngeal carcinoma (NPC), but it also presents as a unique opportunity for intervention by differentiation therapy. Here using RNA-seq profiling analysis and functional assays, we demonstrate that reduced IKKα expression is responsible for the undifferentiated phenotype of NPC. Conversely, overexpression of IKKα induces differentiation and reduces tumorigenicity of NPC cells without activating NF-κB signalling. Importantly, we describe a mechanism whereby EZH2 directs IKKα transcriptional repression via H3K27 histone methylation on the IKKα promoter. The differentiation agent, retinoic acid, increases IKKα expression by suppressing EZH2-mediated H3K27 histone methylation, resulting in enhanced differentiation of NPC cells. In agreement, an inverse correlation between IKKα (low) and EZH2 (high) expression is associated with a lack of differentiation in NPC patient samples. Collectively, these findings demonstrate a role for IKKα in NPC differentiation and reveal an epigenetic mechanism for IKKα regulation, unveiling a new avenue for differentiation therapy.

Aurora-A activation, correlated with hypoxia-inducible factor-1α promotes radiochemoresistance and predicts poor outcome for nasopharyngeal carcinoma

Previously, we and others showed that hypoxia‐inducible factor‐1α (HIF‐1α) and transcriptionally upregulated Aurora‐A were required for disease progression in several tumors. Here, we address the clinicopathologic value of Aurora‐A and HIF‐1α in locally advanced nasopharyngeal carcinoma (NPC). Aurora‐A and HIF‐1α expression was semiquantitatively evaluated by immunohistochemistry staining in 144 cases from a randomized controlled trial. Of these patients, 69 received neoadjuvant chemotherapy plus concurrent chemoradiotherapy, and acted as the training set, and 75 cases treated with neoadjuvant chemotherapy plus radiotherapy were used as the testing set to validate the prognostic effect of Aurora‐A and HIF‐1α. We found that Aurora‐A and HIF‐1α were highly expressed in NPC, but were deficient in normal adjacent epithelia. In the testing set, Aurora‐A overexpression predicted a shortened 5‐year overall survival (59.1% vs 82.5%, P = 0.024), progression‐free survival (44.8% vs 79.8%, P = 0.004), and distant metastasis‐free survival (43.0% vs 17.3%, P = 0.016). Multivariate regression analysis confirmed that Aurora‐A was indeed an independent prognostic factor for death, recurrence, and distant metastasis both in the testing set and overall patients. Moreover, a positive correlation between Aurora‐A and HIF‐1α was detected (P = 0.037). Importantly, although HIF‐1α did not show any prognostic effect for patient outcome, the subset with Aurora‐A and HIF‐1α co‐overexpression had the poorest overall, progression‐free, and distant metastasis‐free survival (all P < 0.05). Our results confirmed that Aurora‐A was an independent prognostic factor for NPC. Aurora‐A combined with HIF‐1α refined the risk definition of the patient subset, thus potentially directing locally advanced NPC patients for more selective therapy. (Cancer Sci, doi: 10.1111/j.1349‐7006.2012.02332.x, 2012)

Serologic Antienzyme Rate of Epstein-Barr Virus DNase-Specific Neutralizing Antibody Segregates TNM Classification in Nasopharyngeal Carcinoma

PURPOSE We investigate the value of pretreatment serologic antienzyme rate (AER) of Epstein-Barr virus (EBV) DNase-specific neutralizing antibody complementing TNM staging in prognostication of nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS Pretreatment serum samples from 1,303 patients with untreated NPC were collected and examined for AER. After a 10-year follow-up period, the prognoses of the patients, classified by their clinical stage with AER, were assessed by multivariate analysis. Of the 1,303 patients, 600 patients were randomly assigned to a training set to generate an AER cutoff point by receiver operating characteristic (ROC) curve analysis. AER levels were then analyzed with overall survival (OS), progression-free survival (PFS), local failure-free survival (LFFS), and distant metastasis-free survival (DMFS) in a testing set (703 patients). Another independent cohort of 464 patients was studied in a validating set. RESULTS In the training set, the ROC analysis-generated AER cutoff point for OS was 58.0%, which was used as the cutoff point in the testing set. The subset of low AER levels predicted a significant survival advantage over the subset of high AER levels for OS, PFS, LFFS, and DMFS in the testing set. Moreover, two distinguished subgroups were segregated by an AER level of 58.0% within each clinical stage comparing prognostication of OS, PFS, LFFS, and DMFS. Importantly, AER level was revealed as the only significant independent prognostic factor for death, recurrence, and distant metastasis in the validating set. CONCLUSION Pretreatment serologic AER of EBV DNase-specific neutralizing antibody serves as an independent prognostic marker complementing TNM stage in NPC. Supplementing pretreatment AER with TNM staging leads to more accurate risk definition in patient subgroups.