Xia He

Effect of Metformin on Cancer Risk and Treatment Outcome of Prostate Cancer: A Meta-Analysis of Epidemiological Observational Studies

Background Laboratory studies have shown the anti-tumor effect of metformin on prostate cancer. However, recent epidemiological studies have yielded inconclusive results. Methods We searched PubMed database from the inception to May 30 2014 for studies which assessed the effect of metformin use on cancer risk of prostate cancer, biochemical recurrence (BCR) and all-cause mortality of patients with prostate cancer. The pooled results and 95% confidence intervals (CIs) were estimated by random-effect model. Results Twenty-one studies were eligible according to the inclusion criteria. Based on the pooled results of available observational studies, metformin use was significantly associated with a decreased cancer risk (14 datasets, 963991 male subjects, odds ratio: 0.91, 95% CI: 0.85–0.97) and BCR (6 datasets, 2953 patients, hazard ratio: 0.81, 95% CI: 0.68–0.98) of prostate cancer. However, the association of metformin use with all-cause mortality of patients with prostate cancer was not significant (5 datasets, 9241 patients, hazard ratio: 0.86, 95% CI: 0.64–1.14). Conclusion Results suggest that metformin use appears to be associated with a significant reduction in the cancer risk and BCR of prostate cancer, but not in all-cause mortality of patients with prostate cancer.

HMGA2 is associated with epithelial–mesenchymal transition and can predict poor prognosis in nasopharyngeal carcinoma

Objective High-mobility group protein 2 (HMGA2) and epithelial–mesenchymal transition (EMT)-associated proteins play key roles in cancer progression and metastasis. However, the clinical significance of HMGA2 and its relationship with EMT markers in nasopharyngeal carcinoma (NPC) is unclear. This study aimed to assess the clinicopathological significance and prognostic value of HMGA2, E-cadherin, and vimentin in NPC. Methods Using immunohistochemistry, HMGA2, E-cadherin, and vimentin expression levels were evaluated in NPC (n=124) and non-tumoral inflammatory nasopharynx (n=20) tissues. The association of HMGA2 and EMT markers with clinicopathological characteristics and relationships between the protein levels and overall survival were analyzed. Results Compared with non-tumorous tissues, HMGA2 and vimentin levels were markedly increased in NPC tissues, whereas decreased E-cadherin levels were observed (P<0.001). Moreover, HMGA2 expression was positively correlated with vimentin levels (r=0.431, P<0.001) and negatively correlated with E-cadherin amounts (r=−0.413, P<0.001) in NPC tissues. The expression of all three proteins correlated significantly with tumor N stage, TNM stage, and 2-year metastasis. Furthermore, significant correlations were found for T stage, N stage, TNM stage, HMGA2, E-cadherin, and vimentin (all P<0.013) with poor prognosis (univariate analysis). However, multivariate analyses showed that only HMGA2 (hazard ratio [HR]: 2.683, 95% confidence interval [CI]: 1.185–6.077, P=0.018) and N stage (HR: 7.892, 95% CI: 2.731–22.807, P<0.001) were independent predictors of poor prognosis. Conclusion These results demonstrated that HMGA2, an independent prognostic factor, may promote NPC progression and metastasis, and is significantly associated with EMT proteins. Therefore, HMGA2 may be considered a potential therapeutic target in NPC.

Delayed-type hypersensitivity (DTH) immune response related with EBV-DNA in nasopharyngeal carcinoma treated with autologous dendritic cell vaccination after radiotherapy.

The aim of this work was to investigate the outcome of an autologous dendritic cell (DC) vaccination in patients with stage II/III nasopharyngeal carcinomas (NPC). From 38 patients with stage II/III Epstein-Barr virus (EBV)-associated NPCs after a radiotherapy, 16 human leukocyte antigen-A2 (HLA-A2)-positive patients were enrolled and medicated with autologous DCs, which were pulsed with HLA-A2-restricted EBV-encoded latent membrane protein 2A (LMP2A) peptides. The lymphocyte subsets, serum cytokines, and EBV-DNA levels as well as the delayed-type hypersensitivity (DTH) responses were determined after vaccination combined with a radiotherapy/chemotherapy. The serum levels of interleukin-2 and interferon-&ggr; (P<0.05) as well as the percentage of natural killer and CD4+T cells increased significantly (P<0.05) after the vaccination. Nine of 16 (56.25%) patients showed a positive skin response to the HLA-A2 restricted EBV LMP2A peptides in a DTH test. The serum EBV-DNA level decreased significantly from 1519±384 to 1214±211 copies/mL in the 9 DTH-positive patients (P=0.0310). No unanticipated or serious toxicity was observed and the vaccine was well tolerated. In conclusion, in NPC patients vaccinated after radiotherapy with autologous DCs, which were pulsed with EBV LMP2A peptides, Th1-specific immune responses were elicited particularly in DTH test positive individuals. The clinical results obtained are encouraging and the EBV-specific HLA-A2-restricted DC vaccination is a promising treatment for EBV-related NPCs.

Downregulating HMGA2 attenuates epithelial-mesenchymal transition-induced invasion and migration in nasopharyngeal cancer cells.

BACKGROUND Epithelial-mesenchymal transition (EMT) is associated with invasion and metastasis of cancer cells. High-mobility group AT-hook 2 (HMGA2) has been found to play a critical role in EMT in a number of malignant tumors. However, whether HMGA2 regulates the EMT in human nasopharyngeal carcinoma (NPC) is unclear. OBJECTIVE The aim of this study was to investigate the effect and mechanism of HMGA2 in inducing invasion and migration in NPC. METHODS In NPC tissues samples, the association of HMGA2 mRNA expression with clinicopathological characteristics were estimated by real-time quantitative RT-PCR(qRT-PCR). In vitro, following the silencing of HMGA2 in CNE-1 and CNE-2 cell lines, the viability and metastatic ability were analyzed using Cell Counting Kit-8 (CCK8), colony formation assay, and transwell assay. EMT and transforming growth factor-beta (TGFβ)/Smad3 signaling pathway-related protein expression changes were evaluated using western blot. RESULTS HMGA2 was upregulated in NPC cell lines and clinical specimens (P < 0.01), and HMGA2 expression correlated significantly with metastasis (P = 0.02) and disease-free survival of NPC (hazard ratio: 3.52; 95% confidence interval: 1.34-7.79; P = 0.01). In addition, following in vitro knockdown of HMGA2, the aggressiveness of cells was markedly inhibited, Vimentin and Snail level was downregulated and E-cadherin expression was upregulated. Moreover, the expression of key proteins TGFβRII and p-Smad3 of the TGFβ/Smad3 signaling pathway was inhibited by the downregulation of HMGA2. CONCLUSION HMGA2 might maintain EMT-induced invasion and migration through the TGFβ/Smad3 signaling pathway in NPC cell lines.

Cetuximab in combination with chemoradiation after induction chemotherapy of locoregionally advanced nasopharyngeal carcinoma: preliminary results

AIM This article aimed to determine treatment compliance, acute toxicities and the short-term curative effects of combining cetuximab with chemoradiation following induction chemotherapy of locoregionally advanced nasopharyngeal carcinoma (NPC). MATERIALS & METHODS A total of 21 patients with locoregionally advanced NPC were scheduled to receive one cycle of induction chemotherapy followed by intensity-modulated radiotherapy, weekly administration of cetuximab and concurrent chemotherapy (at least two cycles with a limit of six). RESULTS All 21 patients completed the planned radiotherapy, 14 patients (67%) without treatment breaks, and 20 patients (95.2%) completed the planned cetuximab therapy. Grade 4 toxicities included leukopenia (seven patients; 33.4%), neutropenia (three patients; 14.3%), thrombocytopenia (one patient; 4.8%) and acneiform rash (one patient; 4.8%). Over a median follow-up period of 13 months (range: 3-23 months), the local, regional and distant control rates were 100, 100 and 95.2%, respectively. CONCLUSION Cetuximab in combination with intensity-modulated radiotherapy and chemoradiation is a feasible strategy against locoregionally advanced NPC. Preliminary survival data are encouraging compared with historic data.

MicroRNA-19b-3p regulates nasopharyngeal carcinoma radiosensitivity by targeting TNFAIP3/NF-κB axis

BackgroundNasopharyngeal carcinoma (NPC) is among the most common squamous cell carcinoma in South China and Southeast Asia. Radiotherapy is the primary treatment for NPC. However, radioresistance acts as a significant factor that limits the efficacy of radiotherapy for NPC patients. Growing evidence supports that microRNAs (miRNAs) play an important role in radiation response.MethodsReal-time quantitative PCR was used to analyze the expression of miR-19b-3p in NPC cell lines and NP69. miR-19b-3p expression profiles in NPC tissues were obtained from the Gene Expression Omnibus database. The effect of miR-19b-3p on radiosensitivity was evaluated by cell viability assays, colony formation assays and in vivo experiment. Apoptosis and cell cycle were examined by flow cytometry. Luciferase reporter assay was used to assess the target genes of miR-19b-3p. Expression of target proteins and downstream molecules were analyzed by Western blot.ResultsmiR-19b-3p was upregulated in NPC and served as an independent predictor for reduced patient survival. Radioresponse assays showed that miR-19b-3p overexpression resulted in decreased sensitivity to irradiation, whereas miR-19b-3p downregulation resulted in increased sensitivity to irradiation in vitro. Moreover, miR-19b-3p decreased the sensitivity of NPC cells to irradiation in vivo. Luciferase reporter assay confirmed that TNFAIP3 was a direct target gene of miR-19b-3p. Knockdown of TNFAIP3 reduced sensitivity to irradiation, whereas upregulation of TNFAIP3 expression reversed the inhibitory effects of miR-19b-3p on NPC cell radiosensitivity. Mechanistically, we found that miR-19b-3p increased NPC cell radioresistance by activating the TNFAIP3/ NF-κB axis.ConclusionsmiR-19b-3p contributes to the radioresistance of NPC by activating the TNFAIP3/ NF-κB axis. miR-19b-3p is a determinant of NPC radioresponse and may serve as a potential therapeutic target in NPC treatment.

Impact of plasma Epstein-Barr virus-DNA and tumor volume on prognosis of locally advanced nasopharyngeal carcinoma.

This retrospective study aims to examine the association of plasma Epstein-Barr virus- (EBV-) DNA levels with the tumor volume and prognosis in patients with locally advanced nasopharyngeal carcinoma (NPC). A total of 165 patients with newly diagnosed locally advanced NPC were identified from September 2011 to July 2012. EBV-DNA was detected using fluorescence quantitative polymerase chain reaction (PCR) amplification. The tumor volume was calculated by the systematic summation method of computer software. The median copy number of plasma EBV-DNA before treatment was 3790 copies/mL. The median gross tumor volume of the primary nasopharyngeal tumor (GTVnx), the lymph node lesions (GTVnd), and the total GTV before treatment were 72.46, 23.26, and 106.25 cm3, respectively; the EBV-DNA levels were significantly correlated with the GTVnd and the total GTV (P < 0.01). The 2-year overall survival (OS) rates in patients with positive and negative pretreatment plasma EBV-DNA were 100% and 98.4% (P = 1.000), and the disease-free survival (DFS) rates were 94.4% and 80.8% (P = 0.044), respectively. These results indicate that high pretreatment plasma EBV-DNA levels in patients with locally advanced NPC are associated with the degree of lymph node metastasis, tumor burden, and poor prognosis.

The role of induction and adjuvant chemotherapy in combination with concurrent chemoradiotherapy for nasopharyngeal cancer: a Bayesian network meta-analysis of published randomized controlled trials

Whether the addition of induction chemotherapy (IC) or adjuvant chemotherapy (AC) to concurrent chemoradiotherapy (CCRT) is superior to CCRT alone for locally advanced nasopharyngeal cancer is unknown. A Bayesian network meta-analysis was performed to investigate the efficacy of CCRT, IC + CCRT, and CCRT + AC on locally advanced nasopharyngeal cancer. The overall survival (OS) with hazard ratios (HRs) and locoregional recurrence rates (LRRs) and distant metastasis rates (DMRs) with risk ratios (RRs) were investigated. After a comprehensive database search, eleven studies involving 2,626 assigned patients were included in this network meta-analysis. Compared with CCRT alone, IC + CCRT resulted in no significant improvement in OS or LRR and a marginal improvement in DMR (OS: HR =0.67, 95% credible interval (CrI) 0.32–1.18; LRR: RR =1.79, 95% CrI 0.80–3.51; DMR: RR =1.79, 95% CrI 0.24–1.04) and CCRT + AC exhibited no beneficial effects on any of the endpoints of OS, LRR, or DMR (OS: HR =0.99, 95% CrI 0.64–1.43; LRR: RR =0.78, 95% CrI 0.43–1.32; DMR: RR =0.85, 95% CrI 0.57–1.24). As a conclusion, for locally advanced nasopharyngeal cancer, no significant differences in the treatment efficacies of CCRT, IC + CCRT, and CCRT + AC were found, with the exception of a marginally significant improvement in distant control observed following IC + CCRT compared with CCRT alone.

ZNF488 enhances the invasion and tumorigenesis in nasopharyngeal carcinoma via the Wnt signaling pathway involving epithelial mesenchymal transition

Purpose The purpose of this study was to investigate the function of Zinc finger protein 488 (ZNF488) in nasopharyngeal carcinoma (NPC). Materials and Methods The endogenous expression of ZNF488 in NPC tissues, normal nasopharyngeal epithelium tissues and NPC cell lines were detected by quantitative reverse transcription polymerase chain reaction. ZNF488 over-expressing and knock-down NPC cell line models were established through retroviral vector pMSCV mediated over-expression and small interfering RNA (siRNA) mediated knock-down. The invasion and migration capacities were evaluated by wound healing and transwell invasion assays in ZNF488 over-expressing and control cell lines. Soft-agar colony formation and a xenograft experiment were performed to study tumorigenic ability in vitro and in vivo. Immunofluorescence and western blotting analysis were used to examine protein changes followed by ZNF488 over-expression. Microarray analysis was performed to explore gene expression profilings, while luciferase reporter assay to evaluate the transcriptive activity of Tcf/Lef. Results ZNF488 was over-expressed in NPC tissues compared with normal tissues, especially higher in 5-8F and S18, which are well-established high metastatic NPC clones. Functional studies indicate that over-expression of ZNF488 provokes invasion, whereas knock-down of ZNF488 alleviates invasive capability. Moreover, over-expression of ZNF488 promotes NPC tumor growth both in vitro and in vivo. Our data further show that over-expression of ZNF488 induces epithelial mesenchymal transition (EMT) by activating the WNT/β-catenin signaling pathway. Conclusion Our data strongly suggest that ZNF488 acts as an oncogene, promoting invasion and tumorigenesis by activating the Wnt/β-catenin pathway to induce EMT in NPC.

Ten-year survival outcomes for patients with nasopharyngeal carcinoma receiving intensity-modulated radiotherapy: An analysis of 614 patients from a single center

OBJECTIVES Intensity-modulated radiotherapy (IMRT) has been applied in nasopharyngeal carcinoma (NPC) for nearly twenty years, while little is known about the ten-year survival outcomes. This study aimed at evaluating the 10-year survival outcomes for patients with NPC receiving IMRT. MATERIALS AND METHODS Data on 614 patients with newly diagnosed, non-disseminated NPC treated by IMRT between 2004 and 2008 were retrospectively reviewed. Survival outcomes stratified by tumor stage were compared. RESULTS The median follow-up duration was 112.7months (range, 7.6-156.8months) for the entire cohort. The 10-year local relapse-free survival rates for T1, T2 and T3 were 94.2%, 92.5% and 91.4% (P>0.05), respectively, and significantly higher than that of T4 disease (79.3%, P<0.05 for all rates). As N category increased from N0 to N3, the 10-year distant metastasis-free survival rates significantly decreased accordingly (P<0.01 for all rates). Furthermore, the 10-year overall survival rates were 100%, 87.1%, 75.5% and 55.6% for stage I, II, III and IV, respectively (P<0.05 except stage I and II). Multivariate analysis established tumor stage and age as independent prognostic factors. Late toxicities were assessable for 495 (80.6%) patients and most were Grade I/II damages. Xerostomia (387 of 489, 79.1%) and hearing impairment (212 of 495, 42.8%) remained the most troublesome. CONCLUSION IMRT could achieve satisfactory survival outcomes for NPC patients with acceptable late toxicities. However, distant control still remains poor, especially for patients with N3 disease.