Exploring the expression of SNHG1 and its effect on the PI3K-AKT axis in nasopharyngeal cancer.

Radiotherapy and chemotherapy have improved the 5-year survival rate of nasopharyngeal carcinoma (NPC) patients, but the side effects generally lead to unsatisfactory clinical efficacy. It's imperative to explore the pathogenesis of NPC to find better diagnostic and therapeutic methods. Small nucleolar RNA host genes (SNHGs) are special lncRNAs, which can be further spliced to produce small nucleolar RNAs (snoRNAs). SNHG1 has been found to be associated with various cancers. However, only a few studies reported the relationship between SNHG1 and NPC. This study first analyzed the diagnostic performance and related signaling pathways of SNHG1 in NPC through bioinformatics. The expression of SNHG1 was verified by RT-qPCR, and the expression of the signaling pathway was detected using immunohistochemistry. Bioinformatics analysis results showed that SNHG1 was significantly overexpressed in head and neck squamous cell carcinoma (HNSC) and NPC tissues. RT-qPCR detection confirmed the significant overexpression of SNHG1 in NPC tissues. Enrichment analysis showed that SNHG1 may act on NPC through the PI3K-AKT signaling pathway. Immunohistochemistry experiment revealed PI3K-AKT signaling pathway proteins (PI3K AKT and EGFR) positively expressed and CASP3 weakly positively expressed in NPC tissues. Therefore, we concluded that SNHG1 is a prospective biomarker and may act on NPC through the PI3K-AKT signaling pathway.

Is CO2 laser microsurgery better than radiotherapy in early glottic cancer: a meta-analysis.

The choice between radiotherapy (RT) and CO2 laser surgery (CO2-LS) for early glottic cancer remains controversial. We systematically examined electronic databases in order to identify prospective trials comparing patients who had undergone CO2-LS or RT to treat early glottic cancer. Eleven studies involving 1053 patients were included. In the selected literature, the parameter setting of CO2 laser equipment can be summarized as wavelength 10.6 µm, superpulsed mode, continuous setting, power tailored on target structures (1-3 W for subtle resections and 4-15 W for cutting a larger tumor), and approximately 2080-3900 W/cm2 of laser energy. Using RevMan 5.3, we estimated pooled odds ratios (ORs) for dichotomous variables and pooled mean differences (MDs) for continuous variables, along with associated 95% confidence intervals (CIs). The heterogeneity in the treatment variables was measured using Higgins' inconsistency test and expressed as I2 values. The continuous variables were then depicted as histograms developed using PlotDigitizer 2.6.8. Compared to patients treated with CO2-LS, those treated with RT had better jitter (MD 1.27%, 95% CI 1.21 ~ 1.32, P < 0.001), and high scores on the "Grade (MD 6.54, 95% CI 5.31 ~ 7.76, P < 0.001), Breathiness (MD 9.08, 95% CI 4.02 ~ 14.13, P < 0.001), Asthenia (MD 2.13, 95% CI 0.29 ~ 3.98, P = 0.02), and Strain (MD 3.32, 95% CI 0.57 ~ 6.07, P = 0.02)" scale. Patients treated with CO2-LS had worse local control rates (OR 3.14, 95% CI 1.52 ~ 6.48, P = 0.002) while lower incidence of second primary tumor (OR 0.30, 95% CI 0.15 ~ 0.61, P < 0.001). It is hoped that retrospective analysis can provide suggestions for early glottis patients to choose personalized treatment.

Nitrative and oxidative DNA damage as potential survival biomarkers for nasopharyngeal carcinoma.

Currently, there are no satisfactory biomarkers available to screen for nasopharyngeal carcinoma (NPC). Nitric oxide (NO), produced by inducible nitric oxide synthase (iNOS), has been suggested to cause nitrative and oxidative stress, leading to the accumulation of 8-nitroguanine (8-NitroG) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) and the subsequent transversion mutation of DNA. The aim of this study was to evaluate iNOS expression and the status of nitrative and oxidative stress in NPC. Fifty-nine cases of NPC and 39 cases of chronic nasopharyngitis were investigated to examine the expression of iNOS and the formation of 8-NitroG and 8-OHdG, using double-immunofluorescent staining. The statistical differences in immunoreactivities were analyzed using the Mann-Whitney test. Thirty-six patients from the 57 cases of NPC and 36 healthy controls were investigated to examine the level of serum 8-OHdG, using enzyme-linked immunosorbent assay (ELISA). The statistical differences were analyzed using a t test. Strong DNA lesions were observed in the cancer cells of NPC patients. All cases of NPC were positive for 8-NitroG and 8-OHdG, and 54 (94.7%) were positive for iNOS. NPC samples exhibited significantly more intense staining for 8-NitroG, 8-OHdG and iNOS than those of chronic nasopharyngitis (P < 0.05, respectively). The mean value of serum 8-OHdG in the 36 NPC patients was 0.538 ± 0.336 ng/ml compared to 0.069 ± 0.059 ng/ml for the healthy controls. The difference in the serum levels of 8-OHdG between the NPC patients and controls was statistically significant (P < 0.05). Our present findings suggest that pathological stimulation of nasopharyngeal tissue, caused by bacterial, viral or parasitic inflammation, may lead to nitrative and oxidative DNA lesions, caused by NO. This may contribute to the cause and development of NPC. Thus, 8-NitroG and 8-OHdG could be potential biomarkers for evaluating the risk of NPC. Better understanding of the molecular mechanisms underlying nitrative and oxidative DNA damage may provide clues to molecular targets for new approaches of NPC prevention.

Effect of 5-ALA-PDT on VEGF and PCNA expression in human NPC-bearing nude mice.

Photodynamic therapy (PDT) is a promising treatment for nasopharyngeal carcinoma. However, recurrence and metastasis of the tumor after PDT remains problematic. In this study we investigated VEGF and PCNA expression in tumor tissues after 5-ALA-PDT. BALB/c nude mice with NPC tumors of similar size were randomly assigned to three groups (n=10 each). In the two treatment groups, mice were administrated 5-ALA intratumorally at a dose of 100 mg/kg and 3-3.5 h prior to laser irradiation (630 nm, 100 J/cm(2), 100 mW/cm(2)). The mice in one of the treatment groups were sacrificed at 24 h after PDT. The other treatment group and control group mice were sacrificed 14 days after PDT, and the tumor weights were determined for all three groups. Mean tumor weights at 14 days after PDT were 1.353+/-0.204 g in the treatment group and 3.124+/-0.380 g in the control group (p<0.001). Results showed the VEGF level in tumor tissues at 24 h after PDT was slightly higher than that in the control group, while it was down-regulated at 14 days after PDT. The PCNA level was not significantly different in tumor tissues among the three groups, but it was lower in degenerated tumor cells 24 h after PDT. Our results suggest that VEGF may play a role in tumor recurrence and metastasis following PDT. Residual tumor cells escaped from PDT is the main reason for tumor recurrence.

Analysis of Epstein-Barr viral DNA load, EBV-LMP2 specific cytotoxic T-lymphocytes and levels of CD4+CD25+ T cells in patients with nasopharyngeal carcinomas positive for IgA antibody to EBV viral capsid antigen.

BACKGROUND: Epstein-Barr virus (EBV) is a herpesvirus commonly associated with several malignant diseases including nasopharyngeal carcinoma (NPC), which is a common cancer in Southeastern Asia. Previous studies showed that plasma levels of EBV-DNA might be a sensitive and reliable biomarker for the diagnosis, staging and evaluating of therapy for NPC. There are a few analyses of the levels of EBV-latent membrane protein 2 (LMP2)-specific cytotoxic T-lymphocytes (CTLs) in patients with NPC. This study was conducted to investigate the levels of EBV-LMP2-specific CTLs, EBV-DNA load and the level of CD4(+)CD25(+) T cells in such patients. METHODS: From February 2006 to April 2006, 62 patients with NPC, 40 healthy virus carriers positive for EBV viral capsid antigen (EBV-IgA-VCA) and 40 controls were enrolled in the study. We used a highly sensitive ELISPOT assay, real-time polymerase chain reaction (PCR) and flow cytometry to measure the EBV-LMP2-specific CTL response, the EBV DNA load and the level of CD4(+)CD25(+) T cells, respectively. RESULTS: The EBV-LMP2-specific CTL responses of the samples from the control, healthy virus carriers and patients with NPC were significantly different from the LMP2 epitopes, with the control and healthy virus carrier samples displaying a stronger response in three cases. There were significant differences in EBV DNA load in serum between NPC and the healthy groups; patients with NPC at stages III or IV had significantly higher viral loads compared with those at stages I or II. A significantly higher percentage of CD4(+)CD25(+) T lymphocytes were detected in the patients, compared with healthy virus carriers and healthy controls. Moreover, patients with advanced stages of NPC (III and IV) had significantly higher percentages than the patients with early stages (I and II). CONCLUSIONS: Patients with NPC are frequently unable to establish or maintain sufficient immunosurveillance to control proliferating B cells harboring EBV and to destroy the tumor cells that express immunodominant LMP2 proteins. Controlling the activity of CD4(+)CD25(+) T cells and elevating CD8(+) cells specific for LMP2 epitopes could be an effective immunotherapy for patients with NPC.

[Dendritic cells transfected with recombinant adenovirus Ad5F35-LMP2 induces LMP2 specific immunity mediated by cytotoxic T lymphocytes in vitro].

OBJECTIVE: To observe whether dendritic cells (DCs) transfected with recombinant adenovirus Ad5F35-LMP2 induces LMP2 specific immunity mediated by cytotoxic T lymphocytes in vitro. METHODS: Dendritic cells have been generated in vitro, and cocultured with autologous T cell after the DCs were infected with Ad5F35-LMP2, then the proliferation of the induced T cells and their cytotoxic activity against CNE-2 tumor cells which express EBV-LMP2 protein on membrane were assessed by MTT method. RESULTS: The dendritic cells could be transfected with Ad5F35-LMP2 and the CTL activated by Ad5F35-LMP2-DC could effectively suppress the proliferation of CNE-2 cells compared with control groups. CONCLUSION: The dendritic cells transfected with recombinant adenovirus Ad5F35-LMP2 showed cytotoxicity effect by activating T lymphocytes.

[Relationship between the expression of TrkB and anoikis resistance in nasopharyngeal carcinoma line].

OBJECTIVE: To study the regulation of anoikis by tyrosine kinase receptor B (TrkB) in human nasopharyngeal carcinoma lines. METHODS; Expression levels of TrkB and brain-derived neurotrophic factor (BDNF) were evaluated by RT-PCR and Western blot. Colony formation ability of C666-1 was observed in soft agar. Proliferation rate and apoptosis, that change in cells by treating the TrkB inhibitor K252a and specificity ligand BDNF respectively under suspension culture, were measured by cell counting kit-8 (CCK-8) assay and the flow cytometry assay. The expression change of TrkB, BDNF and phosphorylation of serine threonine kinase (p-Akt) were investigated by Western blot analysis. RESULTS: TrkB and BDNF were identified in C666-1 cells. C666-1 cells could be decreased the proliferation of colony in soft agar by effect of K252a, but BDNF could make the colony prolific. K252a can inhibit the expression of TrkB in C666-1, and prevent p-Akt activation. And exogenous BDNF stimulated up-regulation TrkB and p-Akt, induced anoikis resistance. CONCLUSION: TrkB inhibits anoikis in nasopharyngeal carcinoma cells. Inhibiton of TrkB by K252a can induce anoikis, and may prove particularly effective in treatment of nasopharyngeal carcinoma.

Reactive nitrogen species-dependent DNA damage in EBV-associated nasopharyngeal carcinoma: the relation to STAT3 activation and EGFR expression.

Nasopharyngeal carcinoma (NPC) is strongly associated with Epstein-Barr virus (EBV) infection. Recently, reactive nitrogen and oxygen species are considered to participate in inflammation-related carcinogenesis through DNA damage. In our study, we obtained biopsy and surgical specimens of nasopharyngeal tissues from NPC patients in southern China, and performed double immunofluorescent staining to examine the formation of 8-nitroguanine, a nitrative DNA lesion and 8-oxo-7,8-dihydro-2'-deoxyguanosine, an oxidative DNA lesion, in these specimens. Strong DNA lesions were observed in cancer cells and inflammatory cells in stroma of NPC patients. Intensive immunoreactivity of iNOS was detected in the cytoplasm of 8-nitroguanine-positive cancer cells. DNA lesions and iNOS expression were also observed in epithelial cells of EBV-positive patients with chronic nasopharyngitis, although their intensities were significantly weaker than those in NPC patients. In EBV-negative subjects, no or little DNA lesions and iNOS expression were observed. EGFR and phosphorylated STAT3 were strongly expressed in cancer cells of NPC patients, but NF-kappaB was not expressed, suggesting that STAT3-dependent mechanism is important for NPC carcinogenesis. IL-6 was expressed mainly in inflammatory cells of nasopharyngeal tissues of EBV-infected patients. EBV-encoded RNAs (EBERs) and latent membrane protein 1 (LMP1) were detected in cancer cells from all EBV-infected patients. In vitro cell system, nuclear accumulation of EGFR was observed in LMP1-expressing cells, and IL-6 induced phosphorylated STAT3 and iNOS. These data suggest that nuclear accumulation of EGFR and STAT3 activation by IL-6 play the key role in iNOS expression and resultant DNA damage, leading to EBV-mediated NPC.

[Immune responses induced by recombinant adenovirus Ad5F35-LMP2 in rhesus monkeys].

OBJECTIVE: To observe the specific cellular and humoral immune responses after immunization with recombinant adenovirus Ad5F35-LMP2 in rhesus monkeys. METHODS: Sixteen rhesuses were immunized with Ad5F35-LMP2 through intra-muscular injection in three groups: high dosage group (1.5 x 10(10) TCID(50)/rhesus), medium dosage group (1.5 x 10(9)TCID(50)/rhesus), low dosage group (1.5 x 10(8)TCID50/rhesus) and the last group was control (PBS 4 ml/rhesus). They were totally immunized three times at intervals of one month. The EBV-LMP2 specific cellular immune responses were tested during the 0, 4, 8, 12 weeks by Elispot after immunization respectively. And the titers of anti-LMP2 antibody were tested by EIA at the same time. RESULTS: EBV-LMP2 specific cellular and humoral immune responses which were induced by recombinant adenovirus Ad5F35-LMP2 can be found in all the three dosage groups. The potency of immune responses was related with the dosage of immunization. Higher dosage elicited more potent immune response. CONCLUSION: The recombinant adenovirus Ad5F35-LMP2 could elicit LMP2 specific cellular and humoral immune responses in rhesus.

[Oral candidal carriage and biotyping of Candida species in HIV positive patients].

OBJECTIVE: To investigate the candidal carriage and the Candida species in HIV positive patients and to explore the relationship between oral candidal carriage and oral candidiasis. METHODS: Sixty-four HIV positive patients and 42 healthy controls were included in this study. Oral rinse technique was used to detect the candidal carriage. The isolates were identified using multiple measures, including Gram staining reaction, chlamydospore, pseudo-hyphal and hyphal production test, CHROMagar Candida test and API 20 C AUX yeast identification system. RESULTS: Thirty-nine of 64 HIV positive cases were diagnosed as oral candidiasis. Seventy-four Candida strains were isolated from 52 of 64 HIV positive cases, only 7 strains were isolated from 42 healthy controls (P < 0.001). Of the 74 Candida strains isolated from HIV positive cases, 39 were Candida albicans, 15 Candida tropicalis, and 20 other 6 species. CONCLUSIONS: A high prevalence of oral candidiasis and high candidal carriage were found in HIV positive patients compared with those in controls. Candida albicans and Candida tropicalis were the major species. The biotyping of the species isolated from HIV positive patients showed more diversified compared to healthy people, which may suggest the decreased immune ability of the HIV positive patients.