OBJECTIVE: To investigate the molecular mechanism of Wnt5a and Epstein-Barr virus latent membrane protein 1 (LMP1) aberrant expression in the nasopharyngeal carcinogenesis and to estimate if it can act as a molecular marker for nasopharyngeal cancer (NPC). METHODS: Immunohistochemistry combined with previously made tissue microarrays were used to study the expression of Wnt5a and LMP1 in the nasopharyngeal carcinogenesis tissues. We investigated the role of over expression of Wnt5a and LMP1 in the development and progression of NPC and their relation with the clinicopathological features of NPC and whether they could act as molecular markers in benign and malignant NPC. RESULTS: The positive percentage of Wnt5a and LMP1 protein expression in the NPC was significantly increased as compared with that in atypically hyperplastic nasopharyngeal epithelium, hyperplastic nasopharyngeal epithelium and histologically normal nasopharyngeal epithelium (P<0.05, P<0.01, and P<0.01). Wnt5a and LMP1 proteins were significantly higher in atypically hyperplastic nasopharyngeal epithelium than those in the hyperplastic nasopharyngeal epithelium and normal nasopharyngeal epithelium (P<0.05 and P<0.01). The positive expression of Wnt5a and LMP1 proteins in clinical T3 and T4 staged NPC was higher than that in clinical T1 and T2 staged NPC (P<0.01 and P<0.05). The positive expression of Wnt5a protein in the NPC with lymph node metastasis was higher than that in the NPC without lymph node metastasis (P<0.01). The positive percentage of LMP1 protein was significantly increased in non-keratinizing carcinoma compared with undifferentiated carcinoma and keratinizing carcinoma (P<0.05 and P<0.05). The expression of Wnt5a protein in the NPC had significant positive correlation with LMP1 (r=0.354, P<0.001). Combined molecular phenotype of both Wnt5a and LMP1 expression was a good marker to distinguish NPC from non-cancerous nasopharyngeal epithelium. CONCLUSION The expression of Wnt5a and LMP1 protein in the NPC is positively correlated, and both wnt5a and LMP1 protein play important roles in the nasopharyngeal carcinogenesis either together or successively promoting the malignant transformation of nasopharyngeal epithelium and the development and progression of NPC. Both Wnt5a and LMP1 positive expression may act as good markers for NPC differential diagnosis.
Biomarkers, Tumor ; genetics ; metabolism ; Carcinogenesis ; Humans ; Nasopharyngeal Neoplasms ; genetics ; metabolism ; pathology ; Oncogene Proteins, Viral ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; metabolism ; Tissue Array Analysis ; Viral Matrix Proteins ; genetics ; metabolism ; Wnt Proteins ; genetics ; metabolism ; Wnt-5a Protein

The heterologously expressed L1 protein of human papilomavirus 16 can assembly into virus-like particles (VLPs), which has been used as prophylactic vaccine for cervical carcinoma. To express L1 protein in Hansenula polymorpha, we analyzed the codon usage of the native gene of L1 protein and redesigned the encoding sequence according to the codon bias of H. polymorpha. We used assembly PCR to synthesize the native gene HPV16L1-N and the codon optimized gene HPV16L1. The synthesized genes were cloned into pMOXZa-A vector to generate plasmids pMOXZ-HPV16N and pMOXZ-HPV16. The expression cassettes MOXp-HPV16L1(N)-AOXTT were cloned into YEp352 vector and transferred into H. polymorpha. After methanol inducement, the expression of L1 protein in H. polymorpha was detected from the codon optimized gene HPV16L1 rather than the native gene HPVI6L1-N. The parameters for induced cultivation for strain HP-U-16L with HPV16L1 were investigated in shaking flask cultures. After induced cultivation in YPM (pH 7.0) medium supplemented with methanol to a final concentration of 1.0% every 12 h at 37 degrees C for 72 h, the recombinant produced 78.6 mg/L of L1 protein. This work offers the possibility for the production of prophylactic vaccine for cervical carcinoma by H. polymorpha.
Capsid Proteins ; biosynthesis ; genetics ; Cloning, Molecular ; Codon ; genetics ; Genetic Vectors ; genetics ; Human papillomavirus 16 ; genetics ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

This study was aimed to identify pET21b-HPV16E2/BL21(DE3) strain and to optimize the expression of human papillomavirus type 16 (HPV16) E2 protein by orthogonal analysis. Four influence factors on two levels were selected to increase the target protein quantity. The four factors were induction time, induction temperature, inductor concentration and cell density. The quantity of HPV16 E2 protein was used as the evaluation parameter. Induced by IPTG, HPV16 E2 protein was analyzed by SDS-PAGE and Western Blot. Target protein was analyzed by GIS imaging system to quantify the protein level. SPSS13. 0 software was applied to analyze the result. Data showed that the expression strain pET211rHPV16 E2/BL21(DE3) was identified correctly. HPV16 E2 protein expressed mainly at insoluble form. The 42KD protein band was identified by SDS-PAGE and Western blot. Orthogonal test was applied on influence factor analysis and expression optimization successfully. Main influence factors were inductor concentration and induction temperature. The optimimum condition of maximum expression quantity was 37 degrees C, 7h, 1.0 mmol/L IPTG and OD600 1.0. In this experiment, orthogonal test could not only be used to analyze the influential factors and promote the target protein expression, but also be used to provide a better experiment method for molecular biological study.
DNA-Binding Proteins ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; Human papillomavirus 16 ; metabolism ; Humans ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; Papillomavirus Infections ; virology ; Recombinant Proteins ; biosynthesis ; genetics

High-risk human papillomavirus (HPV) is the principal cause of various cancers including cervical cancer, anal cancer, vulvar cancer, and some head and neck cancers. In the viral life cycle, by interacting with both viral and host DNA and proteins, the HPV E2 protein plays a pivotal role in viral transcriptional regulation and DNA replication, and it is also associated with modification of various cellular processes, including host gene transcription, RNA processing, apoptosis, ubiquitination, and intracellular trafficking, to create a convenient environment for a replicative cycle of the virus and contribute to the HPV pathogenesis. Elucidating the roles of E2 protein throughout the viral life cycle will improve our understanding of the viral life cycle and pathogenesis and help us identify novel antiviral agents with therapeutic potential. This article reviews the research progress in the structure, roles, and activity of high-risk HPV E2 protein, particularly that of HPV-16.
Animals ; DNA-Binding Proteins ; genetics ; metabolism ; Female ; Gene Expression Regulation, Viral ; Human papillomavirus 16 ; genetics ; metabolism ; Humans ; Oncogene Proteins, Viral ; genetics ; metabolism ; Papillomavirus Infections ; genetics ; metabolism ; virology ; Uterine Cervical Neoplasms ; genetics ; metabolism ; virology

BACKGROUNDHeat shock protein 70 (HSP70) is expressed highly in epithelial tumours associated closely with human papillomavirus 16 (HPV16) infections. However, evidence about the direct relationship between HSP70 expression and HPVs infections are still lacking. In the present study, we examined the expression of HSP70 in keratinocytes introduced with HPV16 E6/E7 oncogenes.

METHODSStable transfected cells were established by transfection of the plasmids pLXSN16E6/E7 into cultured primary keratinocytes and subsequently selected by plasmid specific selection antibiotic (G418) at the required concentration. The expression of HSP70 in pLXSN16E6/E7 transfected keratinocytes was determined by Western blot. The correlation of HSP70 expression and E6/E7 transfection was further confirmed by doubly labelled immunofluorescent staining.

RESULTSCompared to non-transfected keratinocytes, there was a significant trend for higher levels of HSP70 in pLXSN16E6/E7 transfected keratinocytes. Doubly labelled immunofluorescent staining experiment showed that the co-localization of HPV16 E6/E7 and HSP70 in transfected keratinocytes was observed and increased expression of HSP70 was strongly associated with the transfection of HPV16 E6/E7.

CONCLUSIONSOur studies demonstrated increased levels of HSP70 proteins in keratinocytes stably transfected by HPV16 E6/E7 oncogenes. It suggests that the expression of HSP70 is modulated by HPV16 E6/E7 proteins, which may be involved in HPV16 E6/E7 induced immortalization.

Cells, Cultured ; HSP72 Heat-Shock Proteins ; biosynthesis ; Humans ; Keratinocytes ; metabolism ; Oncogene Proteins, Viral ; genetics ; Papillomavirus E7 Proteins ; Repressor Proteins ; genetics ; Transfection

Prokaryotic expression vector of mouse HPV16E6 gene was constructed. A pair of primers were designed according to the digestion sites in plasmid pGEX-KG and the HPV16E6 gene sequence published by GenBank. The DNA fragment of 321bp was amplified by PCR from the HPV recombinant plasmid with HPV16E6 gene, then cloned into pGEX-KG and transformed into the host E. coli strain JM109. The fragment was conformed to the original sequence, which indicated that fusion expression vector pGEX-KG-HPV16E6 was constructed. The pGEX-KG-HPV16E6 plasmid was taken and transformed into BL21(DE3) for expression. Induced by IPTG at 37 degrees C, the expression product of HPV16E6 gene was identified by SDS-PAGE and Western blot. HPV16E6 fusion protein had been expressed successfully in the form of inclusion bodies, the molecular weight of fusion protein being 38 kD. Meanwhile, the optimum condition of HPV16E6 fusion protein expression was induced with 1.0 mmol/L IPTG for 4h. The fusion protein reacted specifically with the antibodies against HPV16E6. HPV16E6 gene was successfully expressed in E. coli, which could be used as a basis for preparing HPV16E6 vaccine in human.
Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Glutathione Transferase ; biosynthesis ; genetics ; Humans ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Repressor Proteins ; biosynthesis ; genetics ; Viral Vaccines ; immunology

The establishment of in vitro model will provide optimal conditions for the study of human papillomavirus (HPV)-associated cervical cancer. In this study, E6 and E7 gens of HPV31 were cloned and expressed in E. coli. The recombinant proteins were purified and used as antigens to immunize mice for the production of polyclonal antibody. Mammalian expression plasmid pBudCE4. 1-HPV31-E6/E7 was also constructed and transfected into C33A cells. The transfected cells were then selected by Zeocin. The expressions of the E6 and E7 mRNAs and proteins were detected by RT-PCR and Western blot respectively. A stable cervical cancer cell line was established as an in vitro model for the study of human papillomavirus type 31(HPV31) associated cervical cancer.
Animals ; Cell Line ; virology ; Female ; Human papillomavirus 31 ; genetics ; metabolism ; Humans ; Mice ; Oncogene Proteins, Viral ; genetics ; metabolism ; Papillomavirus E7 Proteins ; genetics ; metabolism ; Papillomavirus Infections ; virology ; Recombinant Proteins ; genetics ; metabolism ; Transfection

OBJECTIVETo investigate effect of AP-1 and Ets binding site adjacent to matrix metalloproteinase-9 (MMP-9) promoter on activation of MMP-9 transcription of nasopharyngeal carcinoma cells transfected with EBV-encoded latent membrane protein 1 (LMP1), and to ascertain if cross-talk between c-Jun and Ets1 is involved in LMP1-regulating expression of MMP-9.

METHODSSite-directed mutagenesis technique was used to establish a series of mutants, including MMP-9-CAT-Ets(-540)mt, MMP-9-CAT-AP-1(-533)mt and MMP-9-CAT-AP-1(-533)/Ets(-540)mt. After the mutants were transfected into LMP1-expressing NPC HNE2 cells regulated by Tet-on system (pTet-on-LMP1 HNE2), CAT activity of these mutants were assayed with induction of LMP1. With blockade of c-Jun or Ets1 antisense oligonucleotides, the activity of MMP-9 induced by LMP1 was assayed with gelatin zymography.

RESULTSThe CAT activity of MMP-9-Ets(-540)mt-CAT, MMP-9-AP-1(-533)mt-CAT, MMP-9-AP-1(-533)/Ets(-540) mt-CAT decreased significantly compared to MMP-9-CAT wt. After blockade with c-Jun or Ets1 antisense oligonucleotides, activity of MMP-9 induced by LMP1 decreased significantly, especially with combined blockade of c-Jun and Ets1.

CONCLUSIONThe results suggest that transcription factor AP-1 and Ets play an crucial role in activation of MMP-9 transcription induced by LMP1, and cross-talk between c-Jun/Ets1 is involved in expression of MMP-9 mediated by LMP1.

Herpesvirus 4, Human ; genetics ; Humans ; Matrix Metalloproteinase 9 ; biosynthesis ; genetics ; Nasopharyngeal Neoplasms ; metabolism ; virology ; Proto-Oncogene Protein c-ets-1 ; genetics ; Proto-Oncogene Proteins c-jun ; genetics ; Transfection ; Tumor Cells, Cultured ; Viral Matrix Proteins ; genetics

BACKGROUND AND OBJECTIVEEBV BamHI fragment H rightward open reading frame 1 (BHRF1), the Epstein-Barr virus (EBV) early gene, is structurally and functionally homologous to the oncogene bcl-2 and may play an important role in the development of EBV-associated tumors. To characterize the polymorphisms of BHRF1 in EBV-associated tumors, we analyzed the sequences of BHRF1 in isolates from nasopharyngeal carcinoma (NPC) and EBV-associated gastric carcinoma (EBVaGC) biopsies as well as throat washing (TW) samples from healthy donors.

METHODSBHRF1 DNA sequences were analyzed by polymerase chain reaction (PCR) and sequencing for 39 NPC samples, 40 EBVaGC samples, and 53 EBV-positive TW samples from healthy donors. The variants of BHRF1 gene were classified according to the signature changes. The EBV types 1 and 2 at nuclear antigen (EBNA) 3C locus were determined by PCR.

RESULTSCompared with EBV standard cell line B95-8, all isolates carried a silent mutation at amino acid (AA) 80 (nucleotide 54616 T→C), the AA88 L→V mutation was found in most isolates, and the AA79 V→L mutation in a few isolates. Other mutations were sporadically distributed. Based on the mutations at AA88 and AA79, 3 distinct variants of BHRF1 genes, designated as 79V88V, 79L88L, and 79V88L, were identified. The 79V88V was the most common variant. The distribution of the BHRF1 variants among the NPC, EBVaGC, and TW samples was not significant. The corresponding regions of bcl-2 homologues were conserved in all isolates except for 3 samples. The distribution of BHRF1 variants in type 1 and type 2 strains was significant different (P < 0.001, contingency coefficient was 0.554).

CONCLUSIONSThe 79V88V is the dominant variant in NPC, EBVaGC, and TW samples from healthy donors and preferential linkages between BHRF1 and EBNA3C variants exist. Conserved BHRF1 in Bcl-2 homologous domains is helpful to remain the important role of BHRF1.

Carcinoma ; Herpesvirus 4, Human ; genetics ; Humans ; Nasopharyngeal Neoplasms ; genetics ; metabolism ; virology ; Polymorphism, Genetic ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Sequence Analysis, DNA ; Stomach Neoplasms ; genetics ; metabolism ; virology ; Viral Proteins ; genetics ; metabolism

OBJECTIVETo study the effect of As2O3 induction of HeLa cell apoptosis on HPV18 E6 expression and telomerase activity.

METHODSHeLa cells were treated with As2O3 in various concentrations. The effect of As2O3 on HeLa cell survival and apoptosis was determined by MTT assay, light and electron microscopy, and flow cytometry. Telomerase activity in HeLa cells was determined by TRAP-ELISA and the expression of HPV18 E6 mRNA was assayed by RT-PCR.

RESULTSAfter being treated with 2 micromol/L As2O3 for 48 h, the survival of HeLa cells decreased, and marked apoptosis was observed in a time- and dose-dependent manner. There was a good correlation between cell apoptosis and viral E6 gene expression and inhibition of telomerase activity following As2O3 treatment.

CONCLUSIONThe molecular mechanisms of As2O3 effect on HeLa cells may be related to down-regulation of HPV18 E6 oncogene expression and inhibition of telomerase activity.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Arsenicals ; pharmacology ; DNA-Binding Proteins ; biosynthesis ; genetics ; Down-Regulation ; HeLa Cells ; Humans ; Oncogene Proteins, Viral ; biosynthesis ; genetics ; Oxides ; pharmacology ; Telomerase ; metabolism