Xiao-Dong Zhu

Identification of genes involved in radioresistance of nasopharyngeal carcinoma by integrating gene ontology and protein-protein interaction networks.

Radioresistance remains one of the important factors in relapse and metastasis of nasopharyngeal carcinoma. Thus, it is imperative to identify genes involved in radioresistance and explore the underlying biological processes in the development of radioresistance. In this study, we used cDNA microarrays to select differential genes between radioresistant CNE-2R and parental CNE-2 cell lines. One hundred and eighty-three significantly differentially expressed genes (p<0.05) were identified, of which 138 genes were upregulated and 45 genes were downregulated in CNE-2R. We further employed publicly available bioinformatics related software, such as GOEAST and STRING to examine the relationship among differentially expressed genes. The results show that these genes were involved in type I interferon-mediated signaling pathway biological processes; the nodes tended to have high connectivity with the EGFR pathway, IFN-related pathways, NF-κB. The node STAT1 has high connectivity with other nodes in the protein-protein interaction (PPI) networks. Finally, the reliability of microarray data was validated for selected genes by semi-quantitative RT-PCR and Western blotting. The results were consistent with the microarray data. Our study suggests that microarrays combined with gene ontology and protein interaction networks have great value in the identification of genes of radioresistance in nasopharyngeal carcinoma; genes involved in several biological processes and protein interaction networks may be relevant to NPC radioresistance; in particular, the verified genes CCL5, STAT1-α, STAT2 and GSTP1 may become potential biomarkers for predicting NPC response to radiotherapy.

Induction chemotherapy followed by concurrent chemoradiotherapy versus concurrent chemoradiotherapy with or without adjuvant chemotherapy for locoregionally advanced nasopharyngeal carcinoma: meta-analysis of 1,096 patients from 11 randomized controlled trials.

PURPOSE To evaluate the efficacy and toxicity of induction chemotherapy followed by concurrent chemoradiotherapy (the treatment group) versus concurrent chemoradiotherapy with or without adjuvant chemotherapy (the control group) for locoregionally advanced nasopharyngeal carcinoma. METHODS The search strategy included Pubmed, Embase, the Cochrane Library, China National Knowledge Internet Web, Chinese Biomedical Database and Wanfang Database. We also searched reference lists of articles and the volumes of abstracts of scientific meetings. All randomized controlled trials were included for a meta-analysis performed with RevMan 5.1.0. The Grading of Recommendations Assessment, Development, and Evaluation system (GRADE) was used to rate the level of evidence. RESULTS Eleven studies were included. Risk ratios of 0.99 (95%CI 0.72-1.36), 0.37 (95%CI 0.20-0.69), 1.08 (95%CI 0.84-1.38), 0.98 (95%CI 0.75-1.27) were observed for 3 years overall survival, 3 years progression-free survival, 2 years loco-regional failure-free survival and 2 years distant metastasis failure-free survival. There were no treatment-related deaths in either group in the 11 studies. Risk ratios of 1.90 (95%CI 1.24-2.92), 2.67 (95%CI 0.64-11.1), 1.04 (95%CI 0.79-1.37), 0.98 (95%CI 0.27-3.52) were found for grade 3-4 leukopenia, grade 3-4 thrombocytopenia, grade 3-4 mucous membrane, and grade 3-4 hepatic hematologic and gastrointestinal toxicity, the most significant toxicities for patients. CONCLUSION Compared with the control group, induction chemotherapy followed by concurrent chemoradiotherapy was well tolerated but could not significantly improve prognosis in terms of overall survival, loco-regional failure-free survival or distant metastasis failure-free survival.

Poly(ADP-ribose) polymerase-1 regulates the mechanism of irradiation-induced CNE-2 human nasopharyngeal carcinoma cell autophagy and inhibition of autophagy contributes to the radiation sensitization of CNE-2 cells

The aim of the present study was to investigate the role of autophagy in response to ionizing radiation (IR) in CNE-2 human nasopharyngeal carcinoma cells and to demonstrate the function of poly(ADP-ribose) polymerase-1 (PARP-1) in the regulation of IR-induced autophagy. Microtubule-associated protein 1 light chain 3 (LC3) and poly(ADP-ribose) (PAR) were assessed using western blotting. Ultrastructural analysis was performed using transmission electron microscopy (TEM). The percentage of apoptotic cells was assessed by flow cytometry. The MTT method was used to detect cell viability of CNE-2 cells at different time points after IR. Clonogenic survival assays were used to evaluate the radiosensitivity of nasopharyngeal carcinoma cells treated with IR and IR combined with autophagy inhibitor (chloroquine phosphate), with autophagy inducer (rapamycin) or with PARP-1 inhibitor 3-amino benzamide (3AB). IR induced a massive accumulation of autophagosomes detected by TEM and intensified the conversion of cytosolic LC3-I to LC3-II. PARP-1 activation was accompanied by strong upregulation of PAR and LC3-II expression in CNE-2 cells. Compared with radiation alone, chloroquine phosphate (CDP) or 3AB combined with IR significantly decreased cell viability, as well as the autophagic ratio and LC3-II protein levels. Inhibition of autophagy increased radiation-induced apoptosis; rapamycin (RAPA) significantly decreased cell viability as well, but RAPA increased the autophagic ratio and LC3-II protein levels; induction of autophagy increased radiation-induced apoptosis. To conclude, PARP-1 regulates IR-induced autophagy, and PARP-1 inhibitor contributes to the radiation sensitization of CNE-2 cells. Blockade of autophagy with CDP enhanced the cytotoxicity of radiotherapy in CNE-2 cells. This suggests that inhibition of autophagy or PARP-1 may be used as an adjuvant therapy to treat nasopharyngeal carcinoma.

PARP-1 promotes autophagy via the AMPK/mTOR pathway in CNE-2 human nasopharyngeal carcinoma cells following ionizing radiation, while inhibition of autophagy contributes to the radiation sensitization of CNE-2 cells

It was previously reported that poly-(adenosine diphosphate-ribose) polymerase-1 (PARP-1) regulated ionizing radiation (IR)-induced autophagy in CNE-2 human nasopharyngeal carcinoma cells. The present study aimed to investigate whether PARP-1-mediated IR-induced autophagy occurred via activation of the liver kinase B1 (LKB1)/adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway in CNE-2 cells. In addition, the effect of PARP-1 and AMPK inhibition on the radiation sensitization of CNE-2 cells was investigated. CNE-2 cells were treated with 10 Gy IR in the presence or absence of the AMPK activator 5-amino-1-β-D-ribofuranosyl-1H-imidazole-4-carboxamide (AICAR). In addition, IR-treated CNE-2 cells were transfected with lentivirus-delivered small-hairpin RNA or treated with the AMPK inhibitor Compound C. Western blot analysis was used to assess the protein expression of PARP-1, phosphorylated (p)-AMPK, microtubule-associated protein 1 light chain 3 (LC3)-II and p-P70S6K. Cell viability and clone formation assays were performed to determine the effect of PARP-1 silencing and AMPK inhibition on the radiation sensitization of CNE-2 cells. The results showed that IR promoted PARP-1, p-AMPK and LC3-II protein expression as well as decreased p-P70S6K expression compared with that of the untreated cells. In addition, AICAR increased the expression of p-AMPK and LC3-II as well as decreased p-P70S6K expression compared with that of the IR-only group; however, AICAR did not increase PARP-1 expression. Furthermore, PARP-1 gene silencing decreased the expression of PARP-1, p-AMPK and LC3-II as well as increased p-P70S6K expression. Compound C decreased p-AMPK and LC3-II expression as well as increased p-P70S6K expression; however, Compound C did not increase PARP-1 expression. Western blot analysis detected limited expression of p-LKB1 in all treatment groups. Cell viability and clone formation assays revealed that PARP-1 or AMPK inhibition reduced the proliferation of CNE-2 cells following IR. In conclusion, the present study demonstrated that PARP-1 promoted autophagy via the AMPK/mTOR pathway; in addition, PARP-1 or AMPK inhibition contributed to the radiation sensitization of CNE-2 cells following IR. However, it remains to be elucidated whether PARP-1 is an upstream mediator of the LKB1 pathway in CNE-2 cells following IR.

Comparison of Concurrent Chemoradiotherapy Followed by Adjuvant Chemotherapy Versus Concurrent Chemoradiotherapy Alone in Locoregionally Advanced Nasopharyngeal Carcinoma: a Meta-analysis of 793 Patients from 5 Randomized Controlled Trials

PURPOSE The main objective of the present study was to evaluate the efficacy and toxicity of concurrent chemoradiotherapy followed by adjuvant chemotherapy compared with concurrent chemoradiotherapy alone in the treatment of locoregionally advanced nasopharyngeal carcinoma. METHODS The search strategy included Pubmed, Embase, the Cochrane Library, China National Knowledge Internet Web, Chinese Biomedical Database and Wanfang Database. We also searched reference lists of articles and the volumes of abstracts of scientific meetings. Randomized controlled trials (RCTs) that compared concurrent chemoradiotherapy followed by adjuvant chemotherapy with concurrent chemoradiotherapy alone in locoregionally advanced nasopharyngeal carcinoma were included. Meta-analysis was performed with RevMan 5.1.0. The Grading of Recommendations Assessment, Development, and Evaluation system (GRADE) was used to rate the level of evidence. RESULTS Five studies were included. Risk ratios of 1.02 (95%CI 0.89-1.15), 0.93 (95%CI 0.72-1.21), 1.07 (95%CI 0.87-1.32), 0.95 (95%CI 0.80-1.13) were observed for 3 years overall survival, 5 years failure-free survival, 5 years loco- regional failure-free survival and 5 years distant metastasis failure-free survival. There were no treatment-related deaths in both groups of five studies. Hematologic and gastrointestinal toxicity were the most significant for patients during adjuvant chemotherapy. The level of evidence was low. CONCLUSION Compared with concurrent chemoradiotherapy alone, concurrent chemotherapy followed by adjuvant chemotherapy did not improve prognosis. More toxicity was found during adjuvant chemotherapy.

Cognitive function, mood, and sleep quality in patients treated with intensity‐modulated radiation therapy for nasopharyngeal cancer: a prospective study

The aim of this study was to prospectively evaluate the cognitive function, depression, anxiety, and sleep quality in patients with nasopharyngeal cancer (NPC) before and after intensity‐modulated radiotherapy (IMRT).

Short-term versus long-term hormone therapy plus radiotherapy or prostatectomy for prostate cancer: a systematic review and meta-analysis

PurposeTo compare the efficacy and safety of short-term versus long-term hormonotherapy (HT) plus radiotherapy (RT) or prostatectomy (RP) for prostate cancer.MethodsLiteratures were searched from Embase, PubMed, Web of science and Cochrane Library up to October, 2012. Quality of the study was evaluated according to the Cochrane’s risk of bias of randomized controlled trial (RCT); the Grading of Recommendations Assessment, Development and Evaluation System was used to rate the level of evidence. RevMan 5.1 was used for statistical analysis. Two comparisons were of interest: RT plus short-term HT versus RT plus long-term HT and RP plus short-term HT versus RP plus long-term HT. Pooled risk ratio or standardized mean differences were calculated; HT adverse reactions were descriptively evaluated.ResultsNine RCTs (total 4,743 patients) were included, 7 RCTs compared RT plus short-term HT with RT plus long-term HT, 2 RCTs compared RP plus short-term HT with RP plus long-term HT. Meta-analysis showed there was no significant difference in overall survival, disease-free survival and PSA level before RP; long-term was superior to short-term hormonotherapy in biochemical failure rate, clinical progression rate, prostate cancer-specific mortality, positive surgical margin rate and prostate volume before RP. Systematic review demonstrated adverse events caused by the increased length of HT were more common.ConclusionsLong-term HT plus RT showed a trend toward improved overall survival; long-term HT plus RP declined positive surgical margin rate and prostate volume before RP. So, long-term HT may benefit more, but it did not significantly improve the patients’ overall survival, and the adverse reactions are inevitable.

Identification of Radioresistance-Associated Proteins in Human Nasopharyngeal Carcinoma Cell Lines by Proteomic Analysis

BACKGROUND AND PURPOSE Radiotherapy is the mainstay of treatment modality for human nasopharyngeal carcinoma (NPC), but in some cases, the disease is radioresistant. This study aimed to identify proteins potentially responsible for radioresistance of NPC by a proteomic approach. MATERIAL AND METHODS The radioresistant human NPC cell line CNE-2R and its parental cell line CNE-2 were analyzed by two-dimensional gel electrophoresis and matrix-assisted laser desorption/time-of-flight mass spectrometry analysis. The candidate proteins were validated by Western blot analysis. RESULTS In total, 16 differentially expressed proteins were identified; among them, Nm23 H1 was significantly increased, while Annexin A3 was significantly downregulated in CNE-2R cells, compared to CNE-2 cells. CONCLUSIONS Our findings provide a platform for further characterization of the proteins implicated in radioresistance and suggest that these proteins could be exploited as a biomarker for predicting the NPC response to radiotherapy in the clinic.

A Review: Proteomics in Nasopharyngeal Carcinoma

Although radiotherapy is generally effective in the treatment of major nasopharyngeal carcinoma (NPC), this treatment still makes approximately 20% of patients radioresistant. Therefore, the identification of blood or biopsy biomarkers that can predict the treatment response to radioresistance and that can diagnosis early stages of NPC would be highly useful to improve this situation. Proteomics is widely used in NPC for searching biomarkers and comparing differentially expressed proteins. In this review, an overview of proteomics with different samples related to NPC and common proteomics methods was made. In conclusion, identical proteins are sorted as follows: Keratin is ranked the highest followed by such proteins as annexin, heat shock protein, 14-3-3σ, nm-23 protein, cathepsin, heterogeneous nuclear ribonucleoproteins, enolase, triosephosphate isomerase, stathmin, prohibitin, and vimentin. This ranking indicates that these proteins may be NPC-related proteins and have potential value for further studies.

Investigation of long-term survival outcomes and failure patterns of patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: a retrospective analysis

Intensity-modulated radiotherapy (IMRT) has replaced the conventional radiotherapy (2D-RT) and improved clinical efficacy in Nasopharyngeal Carcinoma (NPC) patients. In the present study, we retrospectively analyzed the clinical characteristics of patients with NPC treated with IMRT to assess the long-term survival outcomes and failure patterns. Of the 527 patients, One hundred and twenty-one patients experienced treatment failure, 86 patients developed distant metastases, and 12 patients developed a second primary tumor. The local and regional recurrence rates were 31.4% and 14.0%, respectively. The 5-year overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), regional relapse-free survival (RRFS), and distant metastatic relapse-free survival (DMFS) rates were 80.9%, 75.6%, 91.7%, 96.2%, and 83.0%, respectively. The 5-year LRFS rates of Stage T1-4 patients were 100.0%, 93.1%, 92.0%, and 85.8%, respectively. The 5-year DMFS rates of Stage N0-3 patients were 95.0%, 86.1%, 79.5%, and 67.2%, respectively. Multivariate analysis showed age and T-stage were independent predictors of OS, T-stage was an independent predictor of LRFS, and age and N-stage were independent predictors of PFS and DMFS. In summary, the improved treatment results with IMRT are primarily due to the achievement of a higher local tumor control rate and OS in NPC patients. However, distant metastasis was the most commonly observed failure pattern after treatment. These results provide deep insights about the value of IMRT in the treatment and prognosis of NPC patients.