Search

The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1-mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3beta signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1-silenced cells, indicating that PTEN might be a major mediator of Bmi-1-induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer.

Experimental models that allow investigation of nasopharyngeal carcinoma(NPC) progression could provide valuable insights of the molecular mechanism of nasopharyngeal carcinogenesis as well as potential clinical intervention. Because Epstein-Barr virus only infects humans and a few species of monkeys, representative NPC animal models have not been available so far. Attempts to provide cell models for early nasopharyngeal carcinogenesis have involved in the studies of in vitro transformation of normal finite lifespan human nasopharyngeal epithelial cells (NPEC) to immortality. The first two immortalized NPECs were established by introduction of ectopic SV40T or HPV E6/E7. In order to avoid the unrelated molecular alterations caused by the viral oncogenes, we established and characterized two immortalized NPECs by introduction of Bmi-1, an oncogene which has been demonstrated to be overexpressed in NPC cells and specimens. In addition, human telomerase reverse transcriptase (hTERT) immortalized NPECs have been established in both Tsao's and our laboratory. Unlike the immortalized cells induced by viral oncogenes, these immortal NPECs maintain a normal p53 checkpoint, and are unlikely to have other undefined genetic lesions except presenting some molecular alterations which have been observed in NPC. Thus, the establishment of the immortalized NPECs can be used to further study the mechanism of NPC development using defined genetic elements, particularly in elucidating the role of EBV infection in NPC development.

Background: Centromere protein H (CENP-H) is one of the fundamental components of the human active kinetochore. Recently, CENP-H was identified to be associated with tumorigenesis. This study was aimed to investigate the clinicopathologic significance of CENP-H in tongue cancer., Methods: RT-PCR, real time RT-PCR and Western blot were used to examine the expression of CENP-H in tongue cancer cell lines and biopsies. CENP-H protein level in paraffin-embedded tongue cancer tissues were tested by immunohistochemical staining and undergone statistical analysis. CENP-H-knockdown stable cell line was established by infecting cells with a retroviral vector pSuper-retro-CENP-H-siRNA. The biological function of CENP-H was tested by MTT assay, colony formation assay, and Bromodeoxyuridine (BrdU) incorporation assay., Results: CENP-H expression was higher in tongue cancer cell lines and cancer tissues (T) than that in normal cell and adjacent noncancerous tongue tissues (N), respectively. It was overexpressed in 55.95% (94/168) of the paraffin-embedded tongue cancer tissues, and there was a strong correlation between CENP-H expression and clinical stage, as well as T classification. CENP-H can predict the prognosis of tongue cancer patients especially those in early stage. Depletion of CENP-H can inhibit the proliferation of tongue cancer cells (Tca8113) and downregulate the expression of Survivin., Conclusion: These findings suggested that CENP-H involves in the development and progression of tongue cancer. CENP-H might be a valuable prognostic indicator for tongue cancer patients within early stage.

Background: Lung cancer is 1 of the leading causes of cancer death worldwide, and the high mortality from this disease is caused mainly by the lack of efficient diagnostic strategies for early-stage lung cancer. The objective of the current study was to investigate the expression pattern and clinicopathologic significance of centromere protein H (CENP-H) in patients with nonsmall cell lung cancer (NSCLC)., Methods: The expression profile of CENP-H in normal lung epithelial cells, NSCLC cell lines, NSCLC tissues, and adjacent noncancerous lung tissues were detected by reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR, and Western blot analysis. The expression level of CENP-H in 223 NSCLC tissues was measured by immunohistochemistry staining. Statistical analysis was performed to evaluate the clinicopathologic significance of CENP-H., Results: The expression level of CENP-H was much higher in cancer cell lines and lung cancer tissues than that in normal cells and adjacent noncancerous lung tissues, respectively. Immunohistochemical analysis revealed positive CENP-H expression in 118 of 223 NSCLC tissues (52.9%). Statistical analysis revealed that CENP-H expression was correlated strongly with clinical stage (P=.018), tumor classification (P=.03), and Ki-67 expression (P < .001). Patients with lower CENP-H expression had better overall survival than patients with higher CENP-H expression. Further analysis suggested that CENP-H could predict prognosis only in patients with early-stage disease. Multivariate analysis suggested that CENP-H expression was an independent prognostic marker for survival in patients with NSCLC., Conclusions: The current results demonstrated that high CENP-H protein expression was related to poor outcome in patients with NSCLC. CENP-H may be used as a prognostic biomarker for patients lung patients, especially those with early-stage NSCLC., ((c) 2009 American Cancer Society)

Background and Objective: The prognosis of advanced squamous cell carcinoma of the larynx is poor Prognostic factors of this disease vary in different studies. This study was to analyze the most important factors affecting the prognosis of the patients with advanced (stage III and IV) squamous cell carcinoma (SCC) of the larynx., Methods: Clinical data of 221 patients with advanced SCC of the larynx were retrospectively analyzed. Survival analysis was performed by the life table method; comparison among/between groups was performed using the log-rank test; and multivariate analysis was carried out using the Cox proportional hazard model., Results: The two- and five-year overall survival rates of the 221 patients were 76.9% and 51.1%; while the 2-and 5-year disease free survival rates were 60.0% and 43.0%. Patients in stage III had better prognosis than those in stage IV. Post-operative radiotherapy improved the survival rate in patients with positive surgical margins. There was no difference in the survival rate between patients underwent partial laryngectomy and those underwent total laryngectomy. Multivariate analyses indicated that age, anatomic type, post-surgical stage, surgical margin and radiotherapy influenced the disease free survival (p<0.05), whereas, age, post-surgical stage and surgical margin affected the overall survival (p<0.05)., Conclusions: The prognosis of patients with advanced SCC of the larynx receiving surgery is poor. Age, post-surgical stage and surgical margin are the most important factors affecting the overall survival.

Background: The molecular mechanisms of the development and progression of bladder cancer are poorly understood. The objective of this study was to analyze the expression of Bmi-1 protein and its clinical significance in human bladder cancer., Methods: We examined the expression of Bmi-1 mRNA and Bmi-1 protein by RT-PCR and Western blot, respectively in 14 paired bladder cancers and the adjacent normal tissues. The expression of Bmi-1 protein in 137 specimens of bladder cancer and 30 specimens of adjacent normal bladder tissue was determined by immunohistochemistry. Statistical analyses were applied to test the relationship between expression of Bmi-1, and clinicopathologic features and prognosis., Results: Expression of Bmi-1 mRNA and protein was higher in bladder cancers than in the adjacent normal tissues in 14 paired samples (P < 0.01). By immunohistochemical examination, five of 30 adjacent normal bladder specimens (16.7%) versus 75 of 137 bladder cancers (54.3%) showed Bmi-1 protein expression (P < 0.05). Bmi-1 protein expression was intense in 20.6%, 54.3%, and 78.8% of tumors of histopathological stages G1, G2, and G3, respectively (P < 0.05). Expression of Bmi-1 protein was greater in invasive bladder cancers than in superficial bladder cancers (81.5% versus 32.5%, P < 0.05). In invasive bladder cancers, the expression of Bmi-1 protein in progression-free cancers was similar to that of cancers that have progressed (80.0% versus 82.4%, P > 0.5). In superficial bladder cancers, the expression of Bmi-1 protein in recurrent cases was higher than in recurrence-free cases (62.5% versus 13.7%, P < 0.05). Bmi-1 expression was positively correlated with tumor classification and TNM stage (P < 0.05), but not with tumor number (P > 0.05). Five-year survival in the group with higher Bmi-1 expression was 50.8%, while it was 78.5% in the group with lower Bmi-1 expression (P < 0.05). Patients with higher Bmi-1 expression had shorter survival time, whereas patients with lower Bmi-1 expression had longer survival time (P < 0.05)., Conclusion: Expression of Bmi-1 was greater in bladder cancers than in the adjacent normal tissues. The examination of Bmi-1 protein expression is potentially valuable in prognostic evaluation of bladder cancer.

Purpose: The present study was to investigate the clinical significance of sphingosine kinase 1 (SPHK1), an oncoenzyme, in the development and progression of gastric cancer., Experimental Design: mRNA and protein levels of SPHK1 expression in normal gastric epithelial cells, gastric cancer cell lines, and paired gastric cancer lesions and the adjacent noncancerous tissues were examined using reverse transcription-PCR and Western blotting. Immunohistochemistry was employed to analyze SPHK1 expression in 175 clinicopathologically characterized gastric cancer cases. Statistical analyses were applied to derive prognostic and diagnostic associations., Results: Levels of SPHK1 mRNA and protein were higher in gastric cancer cell lines than in normal gastric epithelial cells. SPHK1 protein level was up-regulated in gastric cancer lesions compared with that in the paired adjacent noncancerous tissues. Gastric cancer tissues from 115 of 175 (65.7%) patients revealed high level of SPHK1 protein expression in contrast to the undetectable or marginally detectable expression of SPHK1 in the adjacent noncancerous gastric tissues. Significantly different expression levels of SPHK1 were found in patients at different clinical stages (P=0.003), T classification (P=0.035), and M classification (P=0.020). Patients with higher SPHK1 expression had shorter overall survival time, whereas those with lower SPHK1 expression survived longer. Further multivariate analysis suggested that SPHK1 up-regulation was an independent prognostic indicator for the disease., Conclusions: SPHK1 protein could be a useful marker for the prognosis of gastric cancer. Further study on the potential use of SPHK1 as a therapeutic target is also warranted.

This paper was to explore bullatacin-mediated multidrug-resistant cell apoptosis at extremely low concentration. To investigate its precise mechanisms, the pathway of cell apoptosis induced by bullatacin was examined. Bullatacin causes an upregulation of ROS and a downregulation of DeltaPsi(m) in a concentration-dependent manner in ABCB1-overexpressing KBv200 cells. In addition, cleavers of caspase-9, caspase-3, and PARP were observed following the release of cytochrome c from mitochondria after bullatacin treatment. However, neither cleavage of caspase-8 nor change of expression level of bcl-2, bax and Fas was observed by the same treatment. Pretreating KBv200 cells with N-acetylcysteine, an antioxidant modulator, resulted in a significant reduction of ROS generation and cell apoptosis induced by bullatacin. Bullatacin-induced apoptosis was antagonized by z-LEHD-fmk, a caspase-9 inhibitor, but not by z-IETD-fmk, a caspase-8 inhibitor. These implied that apoptosis of KBv200 cells induced by bullatacin was associated with the mitochondria-dependent pathway that was limited to activation of apical caspase-9.

Background & Objective: At present, the molecular mechanisms of development and progression of bladder cancer are still poorly understood. This study was to explore the expression and significance of Bmi-1 in bladder cancer, and analyze its correlations to clinicopathologic features and prognosis of bladder cancer., Methods: The expression of Bmi-1 protein in 137 specimens of bladder cancer and 30 specimens of normal bladder tissues was detected by SP immunohistochemistry, and its correlations to clinicopathologic features and prognosis of the patients were analyzed., Results: The positive rate of Bmi-1 protein was significantly higher in bladder cancer than in normal bladder tissues (54.3% vs. 16.7%, P<0.05). The positive rate of Bmi-1 protein was 20.6% in grade G1 bladder cancer, 54.3% in grade G2 bladder cancer, and 78.8% in grade G3 bladder cancer, with significant difference (P<0.05). It was significantly lower in superficial bladder cancer than in invasive bladder cancer (32.5% vs. 81.5%,P<0.05). The expression intensity of Bmi-1 was related to tumor size, classification, TNM stage and prognosis (P<0.05), but not to tumor number and tumor recurrence (P>0.05). The patients were followed up for 44-86 months, with a median of 66 months. The 5-year survival rate was significantly higher in superficial bladder cancer patients than in invasive bladder cancer patients (89.6% vs. 39.2%, P<0.05), and higher in Bmi-1-negative patients than in Bmi-1-positive patients (78.5% vs. 50.8%,P<0.05)., Conclusions: Bmi-1 protein is highly expressed in bladder cancer. Detecting Bmi-1 protein is helpful for diagnosis and prognostic evaluation of bladder cancer.

This study was aimed to identify tumor proteins that elicit a humoral response in patients with esophageal squamous cell carcinoma (ESCC). Autologous sera of 15 newly diagnosed patients with ESCC and age- and gender-matched 15 healthy controls were analyzed individually for antibody-based reactivity against proteins from 15 homogenized ESCC tissue mixture resolved by two-dimensional PAGE. One protein spot, which reacted with sera from ESCC patients but not with those from controls, was identified to be CDC25B by mass spectrometry and Western blotting. High expression of CDC25B was detected in ESCC cell lines and primary tumor tissues, but not in normal esophageal tissues. In addition, CDC25B expression was significantly higher in tumor tissue of patients with sera positive CDC25B-Abs than that of patients without CDC25B-Abs. Finally, anti-CDC25B antibodies were readily detectable in sera from 45 of 124 (36.29%) patients with ESCC, 13 of 150 (8.67%) patients with other types of cancer and 0 of 102 (0%) of healthy individuals. Thus, CDC25B autoantibodies may have clinical utility in ESCC screening and diagnosis.

Background & Objective: DNA double-strand break (DSB) is the main mechanism of tumor cell death after irradiation. Homologous recombination (HR) and DNA nonhomologous end-joining (NHEJ) are two important ways to repair DSB. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an essential protein of NHEJ, plays a major role during DSB. This study was to investigate the expression of DNA-PKcs in nasopharyngeal carcinoma (NPC), and analyze its correlation to the clinicopathologic features and prognosis of NPC., Methods: The expression of DNA-PKcs protein in 223 specimens of NPC tissues was detected by immunohistochemistry. The correlation of DNA-PKcs expression to clinicopathologic features and prognosis of NPC were analyzed., Results: The overexpression rate of DNA-PKcs in 223 NPC specimens was 36.8%. The expression of DNA-PKcs had no significant correlations to gender, age, pathological type and N staging of NPC (P>0.05), but had remarkable correlations to TNM, T and M staging (P<0.05). The 5-year overall survival rate was significantly lower in the patients with overexpression of DNA-PKcs than in those with low expression of DNA-PKcs (54.6% vs. 79.4%, P<0.05). T, N, M staging and the expression of DNA-PKcs were independent predictors for the overall survival of NPC (P<0.05)., Conclusions: DNA-PKcs is positively expressed in the majority of NPC tissues. The expression level of DNA-PKcs is an important factor affecting the prognosis of NPC, which could be used as a prognostic predictor for NPC.

Background: Many kinetochore proteins have been shown to be associated with human cancers. The aim of the present study was to clarify the expression of Centromere protein H (CENP-H), one of the fundamental components of the human active kinetochore, in esophageal carcinoma and its correlation with clinicopathological features., Methods: We examined the expression of CENP-H in immortalized esophageal epithelial cells as well as in esophageal carcinoma cells, and in 12 cases of esophageal carcinoma tissues and the paired normal esophageal tissues by RT-PCR and Western blot analysis. In addition, we analyzed CENP-H protein expression in 177 clinicopathologically characterized esophageal carcinoma cases by immunohistochemistry. Statistical analyses were applied to test for prognostic and diagnostic associations., Results: The level of CENP-H mRNA and protein were higher in the immortalized cells, cancer cell lines and most cancer tissues than in normal control tissues. Immunohistochemistry showed that CENP-H was expressed in 127 of 171 ESCC cases (74.3%) and in 3 of 6 esophageal adenocarcinoma cases (50%). Statistical analysis of ESCC cases showed that there was a significant difference of CENP-H expression in patients categorized according to gender (P = 0.013), stage (P = 0.023) and T classification (P = 0.019). Patients with lower CENP-H expression had longer overall survival time than those with higher CENP-H expression. Multivariate analysis suggested that CENP-H expression was an independent prognostic marker for esophageal carcinoma patients. A prognostic value of CENP-H was also found in the subgroup of T3 approximately T4 and N0 tumor classification., Conclusion: Our results suggest that CENP-H protein is a valuable marker of esophageal carcinoma progression. CENP-H might be used as a valuable prognostic marker for esophageal carcinoma patients.

Interferon-gamma(IFN-gamma) plays an important role in the immunomodulation and growth inhibition of many tumor cells, but its clinical application is limited by its systemic toxicity. Ad/hIFN-gamma, a nonreplicating adenoviral vector encoding human IFN-gamma, has been reported to inhibit tumor growth in vitro and in a xenograft model. In this study, the long-term toxicity of Ad/hIFN-gamma was assessed in cynomolgus macaques (Macaca fascicularis). Thirty animals were enrolled into 5 groups, and administered intramuscularly, respectively, Ad/hIFN-gamma (3.3 x 10(10), 3.3 x 10(11), or 3.3 x 10(12) VP/kg), Ad/LacZ (vector control, 3.3 x 10(11) VP/kg), or excipient 3 times per week for 8 weeks, followed by a 4-week recovery period. At 12 weeks all experimental animals appeared generally healthy, and there were no statistically significant differences in body weight, urinalysis, hemogram, blood biochemistry, and electrocardiogram results between the treatment and control groups. No significant toxic effects were noted on macroscopic and microscopic examinations of organs and tissues. Preliminary investigation of the immunotoxicity of Ad/IFN-gamma indicated that anti-adenoviral and anti-hIFN-gamma antibodies were generated. These data demonstrate that long-term, high-dose intramuscular administration of Ad/IFN-gamma was not notably toxic and might be safe for clinical therapeutic use.

5-Fluorouracil (5-FU) is an important chemotherapeutic agent for nasopharyngeal carcinoma (NPC). However, drug resistance may occur after several cycles of 5-FU-based chemotherapy. The oncogene B-cell-specific Moloney murine leukemia virus insertion site 1 (BMI-1) has been shown to be involved in the protection of cancer cells from apoptosis. In this study, 5-FU treatment could increase the percentage of apoptotic NPC cells among BMI-1/RNAi-transfected cells than that among cells transfected with the empty vector. The 50% inhibitory concentration (IC(50)) values of 5-FU were significantly decreased to a greater extent in the cells transfected with BMI-1/RNAi. Most importantly, the expression of phospho-AKT and the anti-apoptotic protein BCL-2 were downregulated in the cells in which BMI-1 expression was inhibited, whereas the apoptosis-inducer BAX was observed to be upregulated. Abrogation of AKT pathway by a PI3K inhibitor could not further increase the sensitivity to 5-FU in the cells with reduced BMI-1 expression. Taken together, BMI-1 depletion enhanced the chemosensitivity of NPC cells by inducing apoptosis; which is associated with inhibition of the PI3K/AKT pathway.

Purpose: The present study was aimed at clarifying the expression of astrocyte elevated gene-1 (AEG-1), one of the target genes of oncogenic Ha-ras, in breast cancer and its correlation with clinicopathologic features, including the survival of patients with breast cancer., Experimental Design: The expression of AEG-1 in normal breast epithelial cells, breast cancer cell lines, and in four cases of paired primary breast tumor and normal breast tissue was examined using reverse transcription-PCR and Western blot. Real-time reverse transcription-PCR was applied to determine the mRNA level of AEG-1 in the four paired tissues, each from the same subject. Furthermore, AEG-1 protein expression was analyzed in 225 clinicopathologically characterized breast cancer cases using immunohistochemistry. Statistical analyses were applied to test for the prognostic and diagnostic associations., Results: Western blot and reverse transcription-PCR showed that the expression level of AEG-1 was markedly higher in breast cancer cell lines than that in the normal breast epithelial cells at both mRNA and protein levels. AEG-1 expression levels were significantly up-regulated by up to 35-fold in primary breast tumors in comparison to the paired normal breast tissue from the same patient. Immunohistochemical analysis revealed high expression of AEG-1 in 100 of 225 (44.4%) paraffin-embedded archival breast cancer biopsies. Statistical analysis showed a significant correlation of AEG-1 expression with the clinical staging of the patients with breast cancer (P = 0.001), as well as with the tumor classification (P = 0.004), node classification (P = 0.026), and metastasis classification (P = 0.001). Patients with higher AEG-1 expression had shorter overall survival time, whereas patients with lower AEG-1 expression had better survival. Multivariate analysis suggested that AEG-1 expression might be an independent prognostic indicator for the survival of patients with breast cancer., Conclusions: Our results suggest that AEG-1 protein is a valuable marker of breast cancer progression. High AEG-1 expression is associated with poor overall survival in patients with breast cancer.

Background & Objective: Epidermal growth factor receptor (EGFR) is overexpressed in many tumors, and is correlated to poor prognosis. However, the prognostic value of EGFR expression in nasopharyngeal carcinoma (NPC) is controversial. This study was to investigate the expression of EGFR and its phosphorylated form (pEGFR) in NPC, and explore their correlations to the prognosis., Methods: NPC samples were obtained from 110 NPC patients treated at Cancer Center of Sun Yat-sen University from Jan. 1999 to Dec. 1999. The expression of EGFR and pEGFR in 110 specimens of NPC and 20 specimens of normal nasopharyngeal tissues were detected by immunohistochemistry. The correlations of EGFR and pEGFR expression to clinical characteristics and prognosis of NPC were analyzed by univariate and multivariate analyses., Results: The positive rates of EGFR and pEGFR were significantly higher in NPC than in normal tissues (100% vs. 10.0%, 60.0% vs. 15.0%, both P<0.001). High expression rate of EGFR was significantly higher in stage T3-4 tumors than in stage T1-2 tumors (63.6% vs. 43.2%, P=0.034), but it had no relationship with other clinical parameters. The 5-year metastasis-free survival rate was significantly lower in the patients with high pEGFR expression than in those with low pEGFR expression (72.2% vs. 91.0%, P=0.012). However, multivariate analysis revealed that pEGFR expression was not an independent prognostic factor for metastasis-free survival of NPC patients., Conclusion: Phosphorylation of EGFR is related with metastasis-free survival of NPC patients, suggesting an important role of activation of EGFR in the dissemination of NPC.

The efficacy of adenovirus vector-based cancer gene therapy is controversial. Its uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Low transduction is believed to be one of the main barriers as the expression of CAR on tumor cells is frequently reduced. Increasing CAR expression on tumor cells thus offers a promising opportunity for more effective adenovirus based treatment. Expression of CAR in 62 cases of colon tumor specimens were examined with immunohistochemistry. To modify the CAR expression, the effects of proteasome inhibitor MG132 on CAR expression of colon cancer cell lines were determined by flow cytometry, RT-PCR, and western blot. To evaluate adenovirus transfer, we further used rAd.EGFP, rAd.p53, and oncolytic adenovirus to infect target cells. The CAR expression was significantly decreased in colon carcinomas, both in primary tumors and lymphonode metastasis. Though the deregulation of CAR occurred in early disease and showed no relationship with TNM stage, when primary tumors are more than 5 cm in diameter, this deregulation becomes more frequent. More importantly, proteasome inhibitor MG-132 could enhance CAR expression in colon carcinoma cell line lovo, accompanied with enhanced adenovirus transfer, target gene expression, and oncolysis. These data provide a rational basis for evaluation of CAR expression in tumors and pretreatment with CAR conditioner prior to adenovirus vector-based gene therapy.

Background and Objective: The Bmi-1 gene is a transcriptional repressor involved in oncogenesis in various human cancers. Here, we examine Bmi-1 expression in gastric carcinoma (GC) and investigates whether its expression correlates with patient prognosis., Methods: Immunohistochemistry was performed using an anti-Bmi-1 antibody on primary tumor samples of 146 cases of GC. The association between Bmi-1 expression and the clinicopathological status and prognosis of GC patients was statistically analyzed. Furthermore, reverse transcription-PCR (RT-PCR) and Western blotting were performed to determine the expression levels of Bmi-1 in an additional 8 GC and the adjacent non-cancerous samples., Results: Using immunohistochemistry, we found that 99 of 146 paraffin-embedded GC samples expressed Bmi-1 extensively. Statistical analysis showed that Bmi-1 overexpression was highly correlated with tumor size, clinical stage, lymph node metastasis and T classification (P < 0.05), Patients with Bmi-1 expression had shorter overall survival time than those without Bmi-1 expression (P < 0.01). Multivariate analysis indicated that Bmi-1 expression is an independent prognostic factor of GC. RT-PCR and Western blotting showed that Bmi-1 was up-regulated at both the transcriptional and translational levels in the GC tissues compared with the adjacent non-cancerous tissues., Conclusions: Bmi-1 may serve as a valuable marker for diagnosis and prognosis of GC., (2007 Wiley-Liss, Inc)

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV) associated malignancy with high prevalence in Southern Chinese. In order to assess whether defects of EBV-specific immunity may contribute to the tumor, the phenotype and function of circulating T-cells and tumor infiltrating lymphocytes (TILs) were investigated in untreated NPC patients. Circulating naïve CD3+CD45RA+ and CD4+CD25- cells were decreased, while activated CD4+CD25+ T-cells and CD3-CD16+ NK-cells were increased in patients compared to healthy donors. The frequency of T-cells recognizing seven HLA-A2 restricted epitopes in LMP1 and LMP2 was lower in the patients and remained low after stimulation with autologous EBV-carrying cells. TILs expanded in low doses of IL-2 exhibited an increase of CD3+CD4+, CD3+CD45RO+ and CD4+CD25+ cells and 2 to 5 fold higher frequency of LMP1 and LMP2 tetramer positive cells compared to peripheral blood. EBV-specific cytotoxicity could be reactivated from the blood of most patients, whereas the TILs lacked cytotoxic activity and failed to produce IFNgamma upon specific stimulation. Thus, EBV-specific rejection responses appear to be functionally inactivated at the tumor site in NPC.

Background and Objective: [corrected] Dendritic cells play an important role in initiation and regulation of immune responses. Previous studies demonstrated that intratumoral administration of 6Ckine-modified DCs enhanced local and systemic antitumor effects. Herein we report the investigation of the specific CTL responses elicited by adenoviral 6Ckine/IFNgamma fusion gene-modified DCs in vitro., Methods: Human monocyte-derived DCs were modified with an adenoviral vector encoding 6Ckine/IFNgamma fusion protein (Ad-6Ckine/IFNgamma), and then investigated the effect of 6Ckine/IFNgamma fusion protein on the maturation, cytokine and chemokine secretion of DCs, and their activities of recruiting and activating T cells in vitro were investigated., Results: 6Ckine/IFNgamma fusion protein induced DC maturation characterized with the upregulation of CD83 and CCR7. And it up-regulated the expression of RANTES and IL-12p70, down-regulated that of IL-10 in DCs. Additionally, 6Ckine/IFNgamma markedly increased DC's recruiting ability for naive T cells, benefiting from the enhanced expression of chemokines 6Ckine and RANTES in DCs. Fusion gene-modified DCs significantly promoted the proliferation of autologous T cells, induced Th1 differentiation by upregulating the expression of IL-2 and T-bet in T cells, and increased specific cytotoxicity of CTLs against specific tumor cells, HepG2 or LoVo cells, respectively., Conclusion: Combining the effects of 6Ckine and IFNgamma, Ad-6Ckine/IFNgamma modified DCs induced enhanced CTL responses in vitro, which indicated that Ad-6Ckine/IFNgamma modified DCs might be used as an adjuvant to trigger an effective antitumor immune response.

Purpose: Tetrandrine (Tet), a multidrug resistant (MDR) modulator, was a potential candidate for use in cancer therapy and exhibited potent biological activity in vitro and in vivo when combined with anticancer agents such as doxorubicin, paclitaxel. Our aims were to determine whether serum concentration of Tet, which was capable of blocking P-gp in vitro, could be safely achieved in mice and whether Tet induced pharmacokinetic alterations in serum doxorubicin disposition in mice., Methods: Tet of 30 mg/kg dose used to reverse MDR was administrated intraperitoneally in mice. Plasma Tet and serum doxorubicin concentration were analyzed by HPLC. CYP 3A4 activity was examined by HPLC with the substrate of nifedipine., Results: More than 1 micromol/L of Tet could at least tenfold reverse MDR in vitro. The plasma peak concentration of Tet was about 2 micromol/L and not less than 1 micromol/L until 18 h following Tet administration (i.p.) at 30 mg/kg. These suggested that the concentrations of Tet that were sufficient to inhibit P-gp might be achieved in mice receiving 30 mg/kg of Tet. Importantly, no significant difference was demonstrated between the doxorubicin pharmacokinetic parameters obtained in mice received doxorubicin only and doxorubicin plus Tet. This implied that Tet of 30 mg/kg did not alter the profiles of pharmacokinetics of doxorubicin including the clearance and AUC of doxorubicin. Furthermore, Tet did not significantly affect on CYP 3A4 activity in human liver microsomes until more than 25 micromol/L., Conclusions: Tet at the tested dose of combination treatment could achieve plasma concentrations that reversed MDR in experimental models and it had no apparent effect on doxorubicin pharmacokinetics in mice and CYP 3A4 activity in human liver microsomes.

The present study investigated the relationship between DNA-dependent protein kinase (DNA-PK) and radiosensitivity of nasopharyngeal carcinoma (NPC) cell lines. The dose-survival relationship for NPC cell lines, CNE1 and CNE2, was analyzed using clonogenic formation assay, the activity of DNA-PK of the two cell lines was measured using the Signa TECT DNA-PK assay kit, and the localization and expression of Kus (a heterodimer) and DNA-PKcs protein in CNE1 and CNE2 before irradiation and 15 min, 1 h, 6 h, 12 h, 24 h after 4 Gy irradiation were analyzed by immunofluorescence, laser scanning confocal microscope (LSCM) and Western blot. The results showed that the surviving fraction of CNE1 was higher than that of CNE2 at each dose. The DNA-PK activity of CNE1 was also significantly higher than that of CNE2 before and after irradiation (P<0.05), while the expression of total Ku70/Ku80 in CNE1 and CNE2 had no significant difference. Increasing translocation of Ku70 and Ku80 from the cytoplasm to the nuclei in the two cell lines was observed with increase of irradiation time as detected by Western blot, and the immunofluorescence of the DNA-PK complex subunits showed greater nuclear translocation in CNE1 than CNE2 after irradiation. The results suggest that the relatively higher radio-resistance of CNE1 correlates with the higher activity of DNA-PK as compared to that of more radiosensitive CNE2 (or lower radio-resistance) before and after irradiation. Thus, DNA-PK activity may be a useful predictor of radiosensitivity of NPC.

Objective: To analyze the global gene expression profile of primary cultured nasopharyngeal carcinoma (NPC) cells using cDNA microarray techniques to screen new candidate genes related to the occurrence and progression of NPC., Methods: A NPC cell line C666 and primary cultured NPC cells from biopsy specimens in 5 cases were analyzed with microarray techniques in comparison with 3 normal nasopharyngeal epithelial (NPE) biopsy specimens. Several differentially expressed genes identified from the microarray results were verified by fluorescence real-time PCR (FQ-PCR) and immunohistochemistry (IHC)., Results: Primary cultured cells of both NPC and NPE were verified by cytokeratin IHC, EBER1 in situ hybridization and EBV-DNA real-time PCR. Compared with NPE cells, a total of 493 genes in at least 4/6 of the samples were identified to be differentially expressed in the primary cultured NPC cells, including 264 up-regulated and 229 down-regulated ones. Several differentially expressed genes according to the microarray results were confirmed by real-time PCR and IHC., Conclusion: cDNA microarray technique provides an effective and accurate means for global gene expression profiling of primary cultured NPC cells to screen the differentially expressed genes, which may serve as an important basis for studying the mechanism, classification and diagnosis of NPC at the molecular level.

Objective: To investigate the association of B cell-specific MLV integration site-1 (Bmi-1) mRNA expression level with the differentiation, metastasis and prognosis of gastric carcinoma., Methods: Tissue specimens were obtained from 42 patients undergoing surgery for gastric carcinomas. Reverse transcriptional PCR (RT-PCR) was performed for amplification of Bmi-1 mRNA from the 42 tumor tissues and matched adjacent normal tissues, and the differential Bmi-1 mRNA expression was analyzed for its association with the clinical manifestations of the patients., Results: Bmi-1 mRNA expression was detected in all the gastric carcinoma tissues and normal tissues adjacent to the carcinoma using fluorescence method, and in 29 cases, Bmi-1 mRNA expression was significantly higher in the tumor tissues than in the adjacent tissues. Expression of Bmi-1 mRNA was highly correlated with tumor size, lymph node metastasis and T classification (P<0.05), but not with the patients' gender, age, or tumor differentiation (P>0.05). The survival rate was much lower in patients positive for Bmi-1 mRNA expression than in those without Bmi-1 mRNA expression., Conclusions: Bmi-1 mRNA expression is correlated to differentiation and metastasis of gastric carcinoma and may facilitate its prognostic evaluation. Bmi-1 may serve as a marker for assessing the progression of gastric carcinoma and provide assistance for clinical therapeutic decisions.

The Bmi-1 oncogene is overexpressed in a number of malignancies including breast cancer. In addition to Bmi-1, mammalian cells also express four other polycomb group (PcG) proteins that are closely related to Bmi-1. Virtually nothing is known about the role of these PcG proteins in oncogenesis. We have recently reported that Mel-18, a Bmi-1-related PcG protein, negatively regulates Bmi-1 expression, and that its expression negatively correlates with Bmi-1 in proliferating and senescing human fibroblasts. Here, we report that the expression of Bmi-1 and Mel-18 inversely correlates in a number of breast cancer cell lines and in a significant number of breast tumor samples. Overexpression of Mel-18 results in repression of Bmi-1 and reduction of the transformed phenotype in malignant breast cancer cells. Furthermore, the repression of Bmi-1 by Mel-18 is accompanied by the reduction of Akt/protein kinase B (PKB) activity in breast cancer cells. Similarly, Bmi-1 knockdown using RNA interference approach results in down-regulation of Akt/PKB activity and reduction in transformed phenotype of MCF7 cells. Importantly, we show that overexpression of constitutively active Akt overrides tumor-suppressive effect of Mel-18 overexpression and the knockdown of Bmi-1 expression. Thus, our studies suggest that Mel-18 and Bmi-1 may regulate the Akt pathway in breast cancer cells, and that Mel-18 functions as a tumor suppressor by repressing the expression of Bmi-1 and consequently down-regulating Akt activity.

Pyrazolon derivatives were reported to have cytotoxicity to some tumour cells. In the present study, we investigated the effect of Lgf-YL-9 on cytotoxicity and cell apoptosis in human epidermoid carcinoma drug-sensitive parental KB cells and multidrug resistant (MDR) KBv200 cells. Lgf-YL-9 exhibited potent cytotoxicity not only to KB cells but also to KBv200 cells, and the IC(50) were 3.81 and 3.45 microg/mL in KB cells and KBv200 cells, respectively. Importantly, Lgf-YL-9 effectively inhibited tumour growth of KB cell xenografts in nude mice. Lgf-YL-9-induced cell apoptosis was confirmed by chromatin condensation, DNA fragmentation, Annexin-V and propidium iodide (PI) double-staining assay and poly(ADP-ribose) polymerase (PARP) cleavage. Furthermore, Lgf-YL-9-mediated apoptosis in KB cells and KBv200 cells was accompanied by the loss of mitochondrial membrane potential (DeltaPsi(m)), the release of cytochrome c, and the activation of caspases-3, -7, and -9, but not by intercalating to DNA. Although Lgf-YL-9-induced apoptosis was associated with the decrease of DeltaPsi(m), reactive oxygen species (ROS) reduction was interestingly observed in both cell lines. The data suggest that Lgf-YL-9 has similar cytotoxicity to drug-sensitive parental KB cells and MDR KBv200 cells. Lgf-YL-9-induced apoptosis is involved in a new ROS-independent mitochondrial dysfunction pathway, but not in intercalating to DNA.

Members of the evolutionarily conserved Mastermind (MAM) protein family, including the three related mammalian Mastermind-like (MAML) proteins MAML1-3, function as crucial coactivators of Notch-mediated transcriptional activation. Given the recent evidence of cross-talk between the p53 and Notch signal transduction pathways, we have investigated whether MAML1 may also be a transcriptional coactivator of p53. Indeed, we show here that MAML1 is able to interact with p53. We show that MAML1-p53 interaction involves the N-terminal region of MAML1 and the DNA-binding domain of p53, and we use a chromatin immunoprecipitation assay to show that MAML1 is part of the activator complex that binds to native p53-response elements within the promoter of the p53 target genes. Overexpression of wild-type MAML1 as well as a mutant, defective in Notch signaling, enhanced the p53-dependent gene induction in mammalian cells, whereas MAML1 knockdown reduced the p53-dependent gene expression. MAML1 increases the half-life of p53 protein and enhances its phosphorylation/acetylation upon DNA damage of cells. Finally, RNA interference-mediated knockdown of the single Caenorhabditis elegans MAML homolog, Lag-3, led to substantial abrogation of p53-mediated germ-cell apoptotic response to DNA damage and markedly reduced the expression of Ced-13 and Egl-1, downstream pro-apoptotic targets of the C. elegans p53 homolog Cep-1. Thus, we present evidence for a novel coactivator function of MAML1 for p53, independent of its function as a coactivator of Notch signaling pathway.

Background & Objective: Bmi-1, a putative oncogene, is a member of the polycomb group genes family. It is widely expressed in many kinds of tumors. This study was to investigate the expression and significance of Bmi-1 in breast cancer., Methods: The expression of Bmi-1 protein in 58 specimens of breast cancer was detected by immunohistochemistry. The correlation of Bmi-1 expression to clinicopathologic features of breast cancer was analyzed., Results: The intensive positive rate of Bmi-1 in breast cancer was 82.8%. The intensive expression of Bmi-1 was positively correlated to clinical stage and lymph node metastasis (P < 0.05), but not to tumor size, estrogen receptor (ER), progesterone receptor (PR), c-erbB-2 and vascular endothelial growth factor (VEGF) expression (P>0.05)., Conclusions: The intensive expression of Bmi-1 in breast cancer is related to tumor progression. Bmi-1 may serve as a new molecular marker of metastasis of breast cancer.

Objective: To synthesize a novel gadolinium-loaded nanoparticle as a molecular imaging contrast agent for magnetic resonance imaging., Methods: Gadolinium ion was incorporated within a silica nanoparticle. The size of this nanosized particle was determined by using transmission electron microscope. The spin-echo (SE) images of nine nanoparticle dilutions in vitro were obtained from a 1.5 T clinical scanner, compared with gadolinium diethylene triaminepenta acetate (Gd-DTPA). In vivo distribution of nanoparticle in Balb/c nude mice and Balb/c nude mice with nasopharyngeal carcinoma (NPC) xenografted CNE-2 tumors was studied at MR imaging, 30 sec, 5 min, 30 min, 1 h, 2 h, 4 h, and 24 h after intravenous administration., Results: The gadolinium-loaded nanoparticle was short rod-shaped, and approximately 30 to 40 nm in diameter. The value of longitudinal relaxativity (r(1)) of gadolinium nanoparticle was much higher than that of Gd-DTPA. Thirty minutes after injection the gadolinium nanoparticle, the signal intensities of liver, kidney and xenografted tumor increased from 226 +/- 10, 283 +/- 7 and 195 +/- 5 to 352 +/- 12, 328 +/- 10 and 245 +/- 7, respectively. The dynamic MRI scanning showed that gadolinium nanoparticles were mainly distributed in liver after intravenous administration. Strong enhancement was also detected in CNE-2 xenografted tumors., Conclusion: A new gadolinium-loaded nanoparticle with high relaxativity was synthesized successfully, and might serve as a carrier for magnetic resonance molecular imaging.

Purpose: The aim of the present study was to analyze the expression of Centromere protein H (CENP-H), one of the fundamental components of the human active kinetochore, in nasopharyngeal carcinoma (NPC) and to correlate it with clinicopathologic data, including patient survival., Experimental Design: Using reverse transcription-PCR and Western blot, we detected the expression of CENP-H in normal nasopharyngeal epithelial cells, immortalized nasopharyngeal epithelial cell lines, and NPC cell lines. Using immunohistochemistry, we analyzed CENP-H protein expression in 160 clinicopathologically characterized NPC cases. Statistical analyses were applied to test for prognostic and diagnostic associations., Results: Reverse transcription-PCR and Western blot showed that the expression level of CENP-H was higher in NPC cell lines and in immortalized nasopharyngeal epithelial cells than in the normal nasopharyngeal epithelial cell line at both transcriptional and translational levels. By immunohistochemical analysis, we found that 76 of 160 (47.5%) paraffin-embedded archival NPC biopsies showed high expression of CENP-H. Statistical analysis showed that there was a significant difference of CENP-H expression in patients categorized according to clinical stage (P = 0.024) and T classification (P = 0.027). Patients with higher CENP-H expression had shorter overall survival time, whereas patients with lower CENP-H expression had better survival. A prognostic value of CENP-H was also found of the subgroup of N(0)-N(1) tumor classification. Multivariate analysis showed that CENP-H expression was an independent prognostic indicator for patient's survival., Conclusions: Our results suggest that CENP-H protein is a valuable marker of NPC progression. High CENP-H expression is associated with poor overall survival in NPC patients.

Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC) and the viral nuclear antigen 1 (EBNA1) plays a crucial role in viral latency. Three EBNA1 subtypes, P-ala, V-thr and V-val have been detected from healthy carriers in Guangzhou area. A close relation of V-val EBNA1 with NPC was suggested by its preference to infect NPC cells. We therefore investigated the functional difference among these three EBNA1 subtypes in human epithelial cell line. The three coding sequences of the EBNA1 subtypes were cloned into the pGFP-C2 vector, and transfected into 293 cells, respectively. Effect of EBNA1 expression on cell proliferation was examined. The maintenance activity and expression level of EBNA1-plasmid in 293 cells were evaluated by using GFP as a reporter. The expression of P-ala, V-thr or V-val EBNA1 had no effect on 293 cell growth, while the relative average intensity of fluorescence after 14-day selection in V-val-EBNA1/293 cells was statistically higher than P-ala-EBNA1/293 (P<0.05, t test). We suggest that V-val EBNA1 with the functional advantage compared with prototype shown in this study might contribute to the tumorigenesis of NPC by increasing the expression of itself or other viral or cellular genes.

Background & Objective: Except for the tight correlation to nasopharyngeal carcinoma, accumulating evidences show that Epstein-Barr virus (EBV) is correlated to other carcinomas. This study was to investigate the correlation of EBV to colorectal carcinoma in Chinese., Methods: EBV DNA was detected by polymerase chain reaction (PCR) in 90 specimens of primary colorectal carcinoma and 25 specimens of corresponding adjacent non-cancerous tissue, with the primers covering 2 different regions of EBV genome, BamH I W fragment and latent membrane protein 1 (LMP1) exon 3. The expression of EBV nuclear antigen 1 (EBNA1) and LMP1 were determined by immunohistochemistry, and the expression of EBV-encoded RNAs (EBERs) was detected by in situ hybridization., Results: EBV LMP1 exon 3 and W fragment were detected in 27.7% and 32.2% of the 90 colorectal carcinoma specimens, which were significantly higher than the positive rate of EBV gene in the 25 adjacent non-cancerous tissues (4.0%, P<0.001). Of the 29 W fragment-positive tumors, 23 (79.3%) were EBNA1-positive, 1 (3.4%) was EBERs-positive; most EBNA1-positive cells were tumor cells with positive signals gathered in the nuclei. No expression of EBNA1 and EBERs were detected in the 8 W fragment-negative tumors. No expression of LMP1 was detected in all tumor specimens., Conclusion: EBV infection might be associated with colorectal carcinoma in Chinese.

The present study was aimed to determine twist expression in nasopharyngeal carcinoma (NPC) and to investigate the clinicopathological significance in the progress of NPC. Semiquantitative RT-PCR and Western blotting were carried out to investigate the expression of Twist in NPC cell lines and normal nasopharyngeal epithelial cell line, which showed that both Twist mRNA and protein were up-regulated in the tumor cells in comparison with the normal cells. We then examined Twist mRNA expression in non-cancerous nasopharyngeal mucosa (10 cases) and NPC (95 cases) using in situ hybridization. The results showed that Twist was overexpressed in 59 of 95 (62.1%) NPC samples. In contrast, there was no obvious expression of Twist mRNA in non-cancerous tissues. In addition, another 75 NPC samples were analyzed by immunohistochemistry, and 33 of the 75 samples were shown to be positive for Twist protein. Both Twist mRNA expression and Twist protein expression were positively associated with lymph-node metastasis and distant metastasis. Furthermore, expression of Twist protein was correlated with the NPC prognosis. Patients with NPC who were Twist protein-positive had a worse 5-year survival rate. These findings demonstrate that the Twist may play an important role in the invasion and metastasis of NPC. Twist protein is valuable marker for assessing the prognosis of NPC.

Background: Like other herpes viruses, latent Epstein-Barr virus (EBV) infection can be reactivated to lytic replication. Reactivation can be achieved by treatment with various reagents, including tetradecanoyl phorbol acetate (TPA) and Ca2+ ionophores. Relatively little is known about the physiological factors related to reactivation of EBV. Previous studies have demonstrated that G0/G1 cell cycle arrest is associated with EBV activation, and that hypoxic conditions can induce cell cycle arrest. In the present study we investigated the effect of hypoxia on reactivation of EBV., Objective and Methods: Hypoxic culture conditions were established and the expression of Zta protein and the number of EBV DNA copies were measured in B95-8 cells maintained under these conditions., Results: Hypoxia treatment not only increased the expression of the EBV immediate-early protein Zta (which mediates the switch between the latent and lytic form of infection), but also increased the number of EBV DNA copies in B95-8 cells., Conclusions: EBV in latent infection can be activated to lytic infection by hypoxia treatment.

Objective: To investigate the effect of membrane type-1 matrix metalloproteinase (MTI-MMP) on the invasive potential of breast cancer cell and analyze its mechanisms., Methods: After treatment of breast cancer MDA-MB-453 cell line with concanavalin A ( ConA, 20 microg/ml) for 24 h, MT1-MMP protein was detected in cancer cells by Western analysis and immunocytochemistry. MDA-MB-453 cells were cultured with exogenous latent proMMP-2 and MMP-2 activity was analyzed by gelatin zymography. The invasive potential of the tumor cells was measured with a membrane invasion culture system. Cancer cells of the cell line were divided into four groups: the control group treated by neither reagent, group ConA was only treated by ConA, group MMP-2 was treated only by MMP-2, and group ConA + MMP-2 was treated by both ConA and MMP-2. RESULTS The expression of MTI-MMP protein could be detected in groups ConA and ConA + MMP-2, but nothing was detected in control and group MMP-2. There was only 72 000 precursor form of MMP-2 in group MMP-2 and there were both 72 000 precursor form and 64 000 active enzyme form of MMP-2 in group ConA + MMP-2, but there was no forms of MMP-2 in the other two groups detected by gelatin zymography. The largest amount of cells penetrated through Matrigel was observed in group ConA + MMP-2 than in the other three groups., Conclusion: MTI-MMP can remarkably promote the invasive potential of breast cancer cells mainly through its ability of activating latent proMMP-2 to degrade

The Bmi-1 oncoprotein regulates proliferation and oncogenesis in human cells. Its overexpression leads to senescence bypass in human fibroblasts and immortalization of human mammary epithelial cells. In this study, we report that compared with normal nasopharyngeal epithelial cells (NPEC), Bmi-1 is overexpressed in nasopharyngeal carcinoma cell lines. Importantly, Bmi-1 was also found to be overexpressed in 29 of 75 nasopharyngeal carcinoma tumors (38.7%) by immunohistochemical analysis. In contrast to nasopharyngeal carcinoma, there was no detectable expression of Bmi-1 in noncancerous nasopharyngeal epithelium. Moreover, high Bmi-1 expression positively correlated with poor prognosis of nasopharyngeal carcinoma patients. We also report that the overexpression of Bmi-1 leads to bypass of senescence and immortalization of NPECs, which normally express p16(INK4a) and exhibit finite replicative life span. Overexpression of Bmi-1 in NPECs led to the induction of human telomerase reverse transcriptase activity and reduction of p16(INK4a) expression. Mutational analysis of Bmi-1 showed that both RING finger and helix-turn-helix domains of it are required for immortalization of NPECs. Our findings suggest that Bmi-1 plays an important role in the development and progression of nasopharyngeal carcinoma, and that Bmi-1 is a valuable marker for assessing the prognosis of nasopharyngeal carcinoma patients. Furthermore, this study provides the first cellular proto-oncogene immortalized nasopharyngeal epithelial cell line, which may serve as a cell model system for studying the mechanisms involved in the tumorigenesis of nasopharyngeal carcinoma.

Background & Objective: Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC) cells expresses Epstein-Barr nuclear antigen 1 (EBNA1), latent membrane protein 1 (LMP1), and LMP2. LMP2 is an ideal target for immunotherapy because LMP2 mRNA is detected in 100% nasopharyngeal carcinoma cells and LMP2 protein shows stronger immunogenity than the rest 2 viral proteins. This study was to analyze the sequence of CTL epitopes in the transmembrane region of LMP2 to optimize LMP2-targeted immunotherapy., Methods: Genomic DNA was extracted from 20 biopsies of NPC and 3 biopsies of normal nasopharynx from Cantonese. The transmembrane region of LMP2 gene was amplified with hemi-nest polymerase chain reaction (PCR), and then sequenced directly., Results: As compared with prototype B95.8 cells, the transmembrane region of LMP2 gene, derived from Cantonese NPC and normal nasopharynx tissues, had 14 base pair substitutions, resulting in 6 amino acid substitutions. Among these substitutions, 3 changed amino acids were located in 4 HLA-restricted CTL epitopes (SSC, TYG, CLG, and VMS). Among these polymorphisms, the VMS variation was first identified. The sequence changes of the LMP2 derived from NPC was the same as those of the LMP2 from normal nasopharynx, indicating that those variations were due to geographic-associated polymorphisms rather than NPC-associated mutations., Conclusion: Polymorphisms of LMP2 exist in EBV derived from Cantonese, resulting in 4 CTL epitope variations, which implicates that the effect of LMP2 polymorphisms should be considered when LMP2-targeted vaccine is designed for immunotherapy.

Objective: To investigate the patterns of expression of key cell cycle proteins targeting on the human papillomavirus (HPV) sites E6 and E7 in cervical carcinoma., Methods: Semiquantitative immunohistochemistry was used to determine the expression of the cell cycle regulatory factor p53, retinoblastoma gene product pRb, cyclin-dependent kinase inhibitors p21(CIP1/WAF1) (p21), p16(INK4A) (p21), and p27(KIP1) (p21), and cyclin D1 targeting on the HPV sites E6 and E7 in 73 HPV 16-positive specimens of cervical squamous cell carcinoma, 35 from Australia patients and 38 age, lymph node status, and grade of tumor-matched Chinese patients., Results: There were no significant differences in age, lymph node status, and grade of tumor between the Chinese and Australian groups, however, the number of the patients in advanced stage (>Stage IIa) was greater in the Chinese group than in the Australian group (19:7). The positive rate of p53 in the Australian group was 3%, significantly lower than that in the Chinese group (23%, P = 0.028). The upregulation rate of pRb, p21, and p27 in the Australian group were 56%, 63% and 34% respectively, all significantly higher than those in the Chinese group (89%, 97%, and 89% respectively, P = 0.01, P < 0.001, and P < 0.001). There were no significant differences in the upregulation rate of p16 and cyclin D1 expression rate between the Australian group and Chinese group (97% versus 100%, and 3% versus 12%, both P > 0.05). In the combined data of both groups, the positive rate of p53 was 13%; and the upregulation rates of pRb, p16, p21, p27, and cyclin D1 were 74%, 99%, 81%, 63% and 7% respectively., Conclusion: Cervical carcinoma overexpresses pRb, p16, p21, and p27. Tumors from Chinese patients are significantly more likely to be positive in p53 and to have upregulated pRb, p21, and p27 than their Australian counterparts. The molecular pathways to human papillomavirus-induced cervical cancer may be influenced by ethnicity and further investigation is necessary.

Nasopharyngeal carcinoma is a common malignancy in Southeast Asian countries, and genetic background is a well-known component of the complexity underlying its tumorigenic process. We have mapped a nasopharyngeal carcinoma susceptibility locus to chromosome 4p15.1-q12 in a previous linkage study on nasopharyngeal carcinoma pedigrees. In this study provided in this communication, we screened all the genes in this region, with a focus on exons, promoters, and the exon-intron boundary to identify nasopharyngeal carcinoma-associated mutations or functional variants. Importantly, we found a novel gene (LOC344967) with a single nucleotide polymorphism -32G/A in the promoter region. This gene is a member of the acyl CoA thioesterase family that plays an important role in fatty acid metabolism and is involved in the progression of various types of tumors. The -32A variant was found cosegregated with the disease phenotype in the nasopharyngeal carcinoma pedigrees that we previously used for the linkage study. Moreover, this -32A variant creates an activator protein (AP-1)-binding site in the transcriptional regulatory region of LOC344967, which significantly enhanced the binding of AP-1 to the promoter region and the transcription activity of the promoter in vivo. Furthermore, the expression of LOC344967 was significantly up-regulated at both mRNA and protein levels in nasopharyngeal carcinoma cells sharing the -32G/A genotype compared with nasopharyngeal carcinoma cells with the -32G/G genotype. Collectively, these results provide evidence that the -32A variant is a functional sequence change and may be related to nasopharyngeal carcinoma susceptibility in the families studied.

To date, the only entire Epstein-Barr virus (EBV) genomic sequence available in the database is the prototype B95.8, which was derived from an individual with infectious mononucleosis. A causative link between EBV and nasopharyngeal carcinoma (NPC), a disease with a distinctly high incidence in southern China, has been widely investigated. However, no full-length analysis of any substrain of EBV from this area has been reported. In this study, we analyzed the entire genomic sequence of an EBV strain from a patient with NPC in Guangdong, China. This EBV strain was termed GD1 (Guangdong strain 1), and the full-length sequence of GD1 was submitted to the GenBank database. The assigned accession number is AY961628. The entire GD1 sequence is 171,656 bp in length, with 59.5% G+C content and 40.5% A+T content. We detected many sequence variations in GD1 compared to prototypical strain B95.8, including 43 deletion sites, 44 insertion sites, and 1,413 point mutations. Furthermore, we evaluated the frequency of some of these GD1 mutations in Cantonese NPC patients and found them to be highly prevalent. These findings suggest that GD1 is highly representative of the EBV strains isolated from NPC patients in Guangdong, China, an area with the highest incidence of NPC in the world. Furthermore, these findings provide the second full-length sequence analysis of any EBV strain as well as the first full-length sequence analysis of an NPC-derived EBV strain.

Background & Objective: Since three-dimensional culture simulates in vivo microenvironment better than planar culture, the biological character of cells in three-dimensional culture model are more similar with that of living tissues. This study was to establish three-dimensional culture models that represent different stages of nasopharyngeal caicinogenesis, and provide information to elucidate the related molecular events., Methods: Non-tumor nasopharyngeal biopsy specimens were used to culture for normal nasopharyngeal epithelial cells. Early and late passages of normal nasopharyngeal epithelial cell line NPNE2 from nasopharyngeal biopsy specimens, immortalized nasopharyngeal epithelial cell line NP69SV40T, nasopharyngeal carcinoma (NPC) cell line SUNE-1 and its high metastatic subclone 5-8F were cultured in Matrigel to establish three-dimensional models., Results: The cells grew out of non-tumor nasopharyngeal biopsy specimens displayed the morphologic characteristics as epithelia, and could proliferate in vitro for 8-10 passages before senescence. Immunocytochemical staining of cytokeratin revealed that the cells were of epithelial origin. All of the cells, except late passages of NPNE2 cells, could proliferate in the three-dimensional culture system. NPNE2 and NP69SV40T cells mainly developed reticular structures in morphology, and formed few clones with clear and smooth edges as well as tight intercellular junctions. SUNE-1 and 5-8F cells formed clones with irregular morphology, unclear edge, and loose intercellular junctions. In addition, the clones formed by 5-8F cells also developed a lot of pseudopodia, but developed no reticular structure. Late passages of NPNE2 cells formed no clone and reticular structure in the three-dimensional culture., Conclusions: Normal nasopharyngeal epithelial cells can be successfully cultured in vitro from naspharyngeal biopsy specimens. The three-dimensional culture models, established with normal nasopharyngeal epithelial cells, immortalized nasopharyngeal epithelial cells, and NPC cells, may represent the different stages of nasopharyngeal carcinogenesis.

Nasopharyngeal carcinoma (NPC) is a tumor derived from epithelial cells and Epstein-Barr virus infection has been reported to be a cause of this disease. Chemokine receptor CXCR4 was found to be involved in HIV infection and was highly expressed in human malignant breast tumors and the ligand for CXCR4, CXCL12 (SDF-1), exhibited high expression in organs in which breast cancer metastases are often found. The metastatic pattern of NPC is quite similar to that of malignant breast tumors. In this study, we investigated the expression of CXCR4 in nasopharyngeal carcinoma (NPC) tissues by immunohistostaining. We found different staining patterns, which included localization in the nucleus, membrane, cytoplasm or a combination of them. The staining intensity was also variable among samples. The metastatic rates in patients with high compared to low or absent expression was 38.6% versus 19.8%, respectively (P = 0.004). High expression of CXCR4 was associated with poor overall survival (OS = 67.05% versus 82.08%, P = 0.0225). These results suggest that CXCR4 may be involved in the progression of NPC and that a high level of CXCR4 expression could be used as a prognostic factor.