Xiangyang Xue

Potentially predictive microRNAs of gastric cancer with metastasis to lymph node

AIM To detect the expression of 60 microRNAs (miRNAs) in gastric cancer tissues and find new predictive biomarkers of gastric cancer with metastasis. METHODS The expressions of 60 candidate miRNAs in 30 gastric cancer tissues and paired normal tissues were detected by stem-loop real-time reverse transcription-polymerase chain reaction. After primary screening of miRNAs expression, 5 selected miRNAs were further testified in another 22 paired gastric tissues. Based on the expression level of miRNAs and the status of metastasis to lymph node (LN), receiver-operating-characteristic (ROC) curve were used to evaluate their ability in predicting the status of metastasis to LN. RESULTS Thirty-eight miRNAs expressions in gastric cancer tissues were significantly different from those in paired normal tissues (P < 0.01). Among them, 31 miRNAs were found to be up-expressed in cancer tissues and 1 miRNAs were down-expressed ≥ 1.5 fold vs paired normal gastric tissue. Five microRNAs (miR-125a-3p, miR-133b, miR-143, miR-195 and miR-212) were differently expressed between different metastatic groups in 30 gastric cancer biopsies (P < 0.05). Partial correlation analysis showed that hsa-mir-212 and hsa-mir-195 were correlated with the status of metastasis to LN in spite of age, gender, tumor location, tumor size, depth of invasion and cell differentiation. ROC analysis indicated that miR-212 and miR-195 have better sensitivities (84.6% and 69.2%, respectively) and specificities (both 100%) in distinguishing biopsies with metastasis to LN from biopsies without metastasis to LN. CONCLUSION miR-212 and miR-195 could be independent biomarkers in predicting the gastric cancer with metastasis to LN.

Upregulation of long noncoding RNA TUG1 promotes cervical cancer cell proliferation and migration

Long noncoding RNAs (lncRNAs), a novel class of transcripts that have critical roles in carcinogenesis and progression, have emerged as important gene expression modulators. Recent evidence indicates that lncRNA taurine‐upregulated gene 1 (TUG1) functions as an oncogene in numerous types of human cancers. However, its function in the development of cervical cancer remains unknown. The aim of this research was to investigate the clinical significance and biological functions of TUG1 in cervical cancer. TUG1 was found to be significantly upregulated in cervical cancer tissues and four cervical cancer cell lines by quantitative real‐time polymerase chain reaction (qRT‐PCR). Elevated TUG1 expression was correlated with larger tumor size, advanced international federation of gynecology and obstetrics (FIGO) stage, poor differentiation, and lymph node metastasis. Furthermore, knockdown of TUG1 suppressed cell proliferation with activation of apoptosis, in part by regulating the expression of Bcl‐2 and caspase‐3. Silencing of TUG1 inhibited cell migration and invasion via the progression of epithelial–mesenchymal transition (EMT). Taken together, our findings indicate that TUG1 acts as an oncogene in cervical cancer and may represent a novel therapeutic target.

Identification of immunodominant linear B-cell epitopes within the major outer membrane protein of Chlamydia trachomatis

Chlamydia trachomatis is one of the most prevalent sexually transmitted pathogens. Chlamydial major outer membrane protein (MOMP) can induce strong cellular and humoral immune responses in murine models and has been regarded as a potential vaccine candidate. In this report, the amino acid sequence of MOMP was analyzed using computer-assisted techniques to scan B-cell epitopes, and three possible linear B-cell epitopes peptides (VLKTDVNKE, TKDASIDYHE, TRLIDERAAH) with high predicted antigenicity and high conservation were investigated. The DNA coding region for each potential epitope was cloned into pET32a(+) and expressed as Trx-His-tag fusion proteins in Escherichia coli. The fusion proteins were purified by Ni-NTA agarose beads and followed by SDS-PAGE and western blot analysis. We immunized mice with these three fusion proteins. The sera containing anti-epitope antibodies from the immunized mice could recognize C. trachomatis serovars D and E in ELISA. Antisera of these fusion proteins displayed an inhibitory effect on invasion of serovar E by in vitro neutralization assays. In addition, serum samples from convalescent C. trachomatis-infected patients were reactive with the epitope fusion proteins by western blot assay. Our results showed that the epitope sequences selected by bioinformatic analysis are highly conserved C. trachomatis MOMP B-cell epitopes, and could be good candidates for the development of subunit vaccines, which can be used in clinical diagnosis.

Thrombocytosis is a significant indictor of hypercoagulability, prognosis and recurrence in gastric cancer

Although thrombocytosis has been reported in a variety of cancer types, the standard of thrombocytosis in gastric cancer (GC) and the association between thrombocytosis and the clinicopathological features of patients with GC remain unclear. In the present study, 1,763 GC patients were retrospectively filtered by preoperative thrombocytosis and compared with control group A (n=107) that had benign gastric lesions and control group B (n=100) that were GC patients with a normal platelet (PLT) count. Associations between clinical variables and preoperative PLT counts were assessed by univariate and multivariate analyses. Kaplan-Meier survival curves and Cox regression were used to evaluate the effect of thrombocytosis on prognosis. Sensitivities and specificities of the PLT counts in predicting recurrence were analyzed via area under the receiver operating characteristic curve (AUROC). The results indicated that the incidence of thrombocytosis in GC patients was higher than in benign gastric lesion patients, with 4.03% of GC patients having a PLT count >400×109/l (P=0.014) and 12.08% had a PLT count >300×109/l (P<0.001). For the patients with a PLT count >400×109/l, the frequency of abnormal PLT counts in GC correlated with tumor size (P<0.001), tumor, node and metastasis (TNM) classification (P=0.002), invasive degree (P=0.003) and D-dimer (P=0.013) and fibrinogen concentrations (P=0.042). Tumor size (P=0.002), TNM classification (P<0.001) and depth of penetration (P=0.001) were independent factors for thrombocytosis. However, thrombocytosis functioned as an independent prognostic factor for GC patients with a PLT count >400×109/l (relative risk, 1.538; 95% confidence interval, 1.041–2.271). In the majority of patients (17/24) with a high preoperative PLT count that decreased to a normal level following resection, PLT levels increased again at recurrence. Sensitivities and specificities of thrombocytosis for recurrence in those patients were 70.8 and 83.3%, respectively (AUROC, 0.847; P=0.01). Therefore, a PLT count of 400×109/l is a suitable threshold for defining thrombocytosis in GC. Thrombocytosis was shown to affect the blood hypercoagulable state and also have a negative prognostic value for GC patients. PLT monitoring following surgery was useful to predict the recurrence for specific GC patients that suffered preoperative thrombocytosis but had restored PLT levels following resection.

Latent infection of human cytomegalovirus is associated with the development of gastric cancer

The worldwide contagion, human cytomegalovirus (HCMV), may cause a series of disorders in infected individuals. The aim of the present study was to investigate whether HCMV infection is associated with the development of gastric cancer. In this study, the positive expression of unique long (UL)133-UL138 and immediate-early (IE)1 genes, which are associated with viral latency and replication, respectively, were detected using nested polymerase chain reaction. A χ2 test and logistic regression analysis were performed to further investigate the preliminary data. The data indicated that the positive rate of UL133, UL135 and UL136 expression in cancer tissues was higher than that in paired normal tissues (P=0.01, 0.027 and 0.013, respectively). However, no significant differences were identified in the UL133–138 locus and IE1 gene when associated with clinicopathological features. Furthermore, seven infection patterns were identified, with the UL133 + UL138 infection pattern representing the largest proportion in the cancer (60.34%) and normal tissues (42.11%). In conclusion, it is possible that the UL133–UL138 locus is important in the occurrence of gastric cancer. The mechanism by which UL133–UL138 locus expression differs in human gastric cancer requires further investigation.

Codon usage bias in human cytomegalovirus and its biological implication.

Human cytomegalovirus (HCMV) infection, a worldwide contagion, causes a serious disorder in infected individuals. Analysis of codon usage can reveal much molecular information about this virus. The effective number of codon (ENC) values, relative synonymous codon usage (RSCU) values, codon adaptation index (CAI), and nucleotide contents was investigated in approximately 160 coding sequences (CDS) among 17 human cytomegalovirus genomes using the software CodonW. Linear regression analysis and logistic regression were performed to explore the preliminary data. The results showed that, overall, HCMV genomes had low codon usage bias (mean ENC=47.619). However, the ENC of individual CDS varied widely and was distributed unevenly between host-related genes and viral-self-function genes (P=0.002, odds ratio (OR)=3.194), as did the GC content (P=0.016, OR=2.178). The ENC values correlated with CAI, GC content, and the nucleotide composing at the 3rd codon position (GC3s) (P<0.001). There was a significant variation in the codon preference that depended on the RSCU data. The predicted ENC curve suggested that mutational pressure, rather than natural selection, was one of the main factors that determined the codon usage bias in HCMV. Among 123 genes with known function, the genes related to viral self-replication and viral-host interaction showed different ENC and CAI values, and GC and GC3s contents. In conclusion, the detailed codon usage bias theoretically revealed information concerning HCMV evolution and could be a valuable additional parameter for HCMV gene function research.

Correlation between systemic lupus erythematosus and cytomegalovirus infection detected by different methods

Human cytomegalovirus (HCMV), a β-herpes virus subfamily member, leads to a lifelong, latent infection in most humans, but the correlation between HCMV infection and systemic lupus erythematosus (SLE) remains controversial. We analyzed the relevance of HCMV infection in SLE by analyzing the peripheral blood leukocytes (PBLs) and serum samples of 60 patients with SLE and 111 healthy individuals. HCMV genes UL55 and UL138 were detected in PBLs by polymerase chain reaction (PCR), and HCMV-specific serum IgG and IgM antibodies were investigated by enzyme-linked immunosorbent assay. The relationship between cellular HCMV infection in PBLs and common clinical indicators of SLE was further explored. Data indicated that the frequency of positive IgG and IgM anti-CMV antibodies was not significantly different in SLE patients and controls. However, compared to the healthy controls, the titers of IgG and IgM anti-CMV antibodies in SLE patients were significantly higher. The detection of cellular HCMV infection showed that almost all subjects were positive for UL138 gene in PBLs, but the positivity for UL55 gene was lower in PBLs. HCMV UL138 detection in PBLs was highly consistent with the frequency of the HCMV-specific IgG test and did not show significant difference in SLE patients and healthy controls. However, compared with that in healthy people, the positivity rate for cellular HCMV UL55 detection was significantly higher in SLE patients (P < 0.001). In addition, cellular HCMV UL55 with positive detection in PBLs was associated with significantly different clinical characteristics of SLE than that with negative detection. In conclusion, our data confirmed that the HCMV infection was related to the development of SLE. Especially, some clinical strains or substrains of HCMV, such as containing the UL55 gene in HCMV’s genome, might play a vital role in the development of SLE.

Hepatitis B virus core antigen as a carrier for Chlamydia trachomatis MOMP multi-epitope peptide enhances protection against genital chlamydial infection.

Chlamydia trachomatis (Ct) is the leading cause of sexually transmitted diseases worldwide. There is no safe and effective vaccine to control the spread of Ct. In development of Ct vaccine, selection of appropriate candidate antigens and an effective delivery system may be the main challenges. Multi-epitope of major outer membrane protein (MOMPm) is the most suitable candidate for a Ct vaccine, while hepatitis B virus core antigen (HBcAg) has unique advantages as vaccine delivery system. Therefore, in this study, we evaluated the immunogenicity and protective immune response of a novel candidate vaccine in a murine model of chlamydial genital infection. This candidate vaccine comprises MOMPm peptide delivered with HBcAg. Our results of Ct-specific serum IgG and secretory IgA assay, cytokine assay, and cytotoxic T-lymphocyte assay revealed that immunogenicity of the candidate vaccine was much better than that of the corresponding synthetic MOMPm peptide. Furthermore, the protective effect of the candidate vaccine was also shown much better than that of the synthetic peptide by calculating the isolation of Chlamydia from vaginal swabs and histopathological analysis. Taken together, our results indicate that HBcAg carrying Ct MOMPm could be an effective immune prophylactic for chlamydial infection.

Hepatitis B virus surface antigen as delivery vector can enhance Chlamydia trachomatis MOMP multi-epitope immune response in mice.

Chlamydia trachomatis is the leading cause of sexually transmitted infections worldwide. There is currently no commercially available vaccine against C. trachomatis. Major outer membrane protein (MOMP) of C. trachomatis is considered to be an ideal candidate for prophylactic vaccine. We designed a MOMP multi-epitope containing T- and B-cell epitope-rich peptides and developed hepatitis B surface antigen (HBsAg) as antigen delivery vehicle. In order to study the immunogenicity and efficacy of the candidate vaccine in a murine model of chlamydial genital infection, we engineered a recombinant plasmid expressing HBsAg and MOMP multi-epitope genes. Results of reverse transcription polymerase chain reaction and immunofluorescence assay revealed successful expression of the recombinant HBsAg/MOMP multi-epitope gene at both the transcription and translation levels. Intramuscular administration in mice was able to elicit not only antibodies against Chlamydia and HBsAg but also cytotoxic T lymphocyte activity against Chlamydia. In addition, mice inoculated with the rHBsAg were highly resistant to C. trachomatis genital infection. The rHBsAg DNA with MOMP multi-epitope appended at the C terminus of the HBsAg stimulated a stronger immune response and protective response than that appended at the N terminus. Together, our results suggested that use of a recombinant HBsAg encoding the MOMP multi-epitope could be a powerful approach to developing a safe and immunogenic C. trachomatis vaccine.

Evaluation of tandem Chlamydia trachomatis MOMP multi-epitopes vaccine in BALB/c mice model

Chlamydia trachomatis (Ct), an obligate intracellular parasite, is the leading cause of bacterial sexually transmitted diseases worldwide. The best solution to control the spread of Ct is to develop safe and effective vaccines. However, an effective vaccine has not been developed due to some challenges such as selection of appropriate candidate antigens and an effective delivery system. In our previous study, we have developed a Ct vaccine that comprises a multi-epitope peptide of Ct major outer membrane protein (MOMP370-387) and Hepatitis B virus core antigen (HBcAg). The vaccine was evaluated in a murine model with chlamydial genital infection. The results indicated that Ct MOMP multi-epitope delivered by HBcAg could be an effective vaccine for the prevention of Ct. In this study, another two epitopes were selected from the MOMP protein and tandemly linked with MOMP370-387 to enhance the immunogenicity and the protective effect of the candidate vaccine. Our results revealed that both the immunogenicity and the protective effect of the tandem Ct MOMP multi-epitopes were much better than that of the single epitope. Therefore, vaccines based on the tandem Ct MOMP multi-epitopes could be more effective immune prophylactics to prevent Ct infection than the single epitope in murine model system.