Human papillomavirus E7 (HPV E7) is a viral oncoprotein that plays an important role in cervical carcinogenesis through binding with retinoblastoma protein (Rb). Inactivation of Rb by E7 is necessary but not sufficient for cellular transformation, suggesting other protein-protein interactions are required for E7-mediated cellular transformation aside from the interaction with Rb. However, studies on the oncogenic function of HPV E7 have been limited by its poor immunoreactivity. In this report, we show that the fixation of purified recombinant HPV E7 on blotted nitrocellulose membrane with glutaldehyde markedly enhanced the immunoreactivity of HPV E7 protein. Using HeLa and Caski cell line which are infected with HPV 18 and HPV 16, respectively, we demonstrated that native HPV E7 proteins also could be detected by this method. These results therefore can provide the experimental conditions for detection of HPV E7 proteins with greater sensitivity and may help to analyze E7 functions.
Cell Extracts/chemistry/immunology ; Cell Line ; Human ; Immunochemistry/*methods ; Oncogene Proteins, Viral/*analysis/immunology ; Papillomavirus, Human/chemistry/*immunology

A simple, rapid and sensitive colorimetric loop mediated isothermal amplification (LAMP) method was established to detect HPV6 and HPV 16 respectively. The method employed a set of four specially designed primers that recognized six distinct sequences of HPV6-E6 or HPV16-E7 for amplification of nucleic acid under isothermal conditions at 63 degrees C for one hour. The amplification process of LAMP was monitored by the addition of HNB (hydroxy naphthol blue) dye prior to amplification. A positive reaction was indicated by a color change from violet to sky blue and confirmed by real-time turbidimeter and agarose electrophoresis. Thirteen cervical swab samples having single infection with 13 different HPV genotypes were examined to evaluate the specificity. A serial dilution of a cloned plasmid containing HPV-E6 or HPV-E7 gene was examined to evaluate the sensitivity. The results showed that no cross-reaction with other HPV genotypes was observed. The colorimetric LAMP assay could achieve a sensitivity of 1000 copies, 10-20 times lower than that of real-time PCR. The assay was further evaluated with 62 clinical specimens and consistent results were obtained compared with the detection using Kai Pu HPV Genotyping Kit. We concluded that this colorimetric LAMP assay had potential usefulness for the rapid screening of the HPV6 or HPV16 infection in the laboratories and hospitals of provincial and municipal region in China.
Colorimetry ; methods ; DNA Primers ; chemistry ; genetics ; Genotype ; Human papillomavirus 16 ; genetics ; isolation & purification ; Human papillomavirus 6 ; genetics ; isolation & purification ; Humans ; Nucleic Acid Amplification Techniques ; instrumentation ; methods ; Papillomavirus Infections ; virology

OBJECTIVETo explore the in vitro inhibitive effect and underlying mechanisms of Brucea Javanica oil emulsion (BJOE) on human papilloma virus (HPV) type 16 infected cells.

METHODSThe HPV16 E61E7 immortalized human ectocervical Ect1/E6E7 cell line and the CaSki cell line were selected as the in vitro models of premalignant cervical lesion and cervical cancer respectively. After treated with BJOE at different concentrations (5, 10, 20, and 40 microg/mL) at the operation time points (24, 48, and 72 h), the effects of BJOE on proliferative activities were measured by MTT assay. The morphologic changes of cell apoptosis stained with Hochest 33,258 were observed by fluorescence microscope. The effect on the cell apoptosis rate was analyzed by Annexin V-FITC/PI double-labeled flow cytometry. The mRNA expressions of HPV16 E6 and E7 were determined by semi-quantitative RT-PCR. The protein expressions of HPV16 E6, E7 oncogene, and specifically interacted p53, Rb antioncogene were stained by immunocytochemical staining (Elivison two-step procedure).

RESULTS(1) The proliferative activities of the Ect1/E6E7 cell and the CaSki cell treated with BJOE at different concentrations (5, 10, 20, and 40 p g/mL) at the operation time points (24, 48, and 72 h) were obviously inhibited, showing dose- and time-dependent manners (P <0.05). (2) Typical changes of apoptosis were observed in both HPV 16 positive cell lines after treated with BJOE. The cell apoptosis rates increased markedly after being cultured with BJOE at different concentrations (5, 10, and 20 microg/mL) for 48 h (P < 0.05). (3) After treated with BJOE at different concentrations (5, 10, and 20 microg/mL) for 48 h, the HPV16 E6 and E7 mRNA relative expressions in both HPV 16 positive cell lines decreased significantly (P < 0.05). (4) After treated with BJOE at different concentrations (5, 10, and 20 microg/ mL), the expressions of HPV16 E6, E7, and mutant p53 protein decreased gradually (P < 0.05), while the Rb protein expression increased gradually (P < 0.05).

CONCLUSIONSBJOE showed obvious in vitro inhibitory effects on HPV type 16 infected cells. Its underlying mechanisms might be possibly associated with down-regulating expressions of HPV16 E6 and E7 oncogenes.

Apoptosis ; drug effects ; Brucea ; chemistry ; Cell Line, Tumor ; Drugs, Chinese Herbal ; pharmacology ; Female ; Human papillomavirus 16 ; drug effects ; pathogenicity ; Humans ; Oncogene Proteins, Viral ; metabolism ; Papillomavirus E7 Proteins ; metabolism ; Papillomavirus Infections ; Plant Oils ; pharmacology ; Repressor Proteins ; metabolism

Papillary immature metaplasia (PIM) is a distinctive exophytic lesion of the uterine cervix and shares some histologic and cytologic features with ordinary squamous metaplasia (SM), atypical immature squamous metaplasia (AIM), high-grade squamous intraepithelial neoplasia (HSIL) and papillary squamous cell carcinoma (PSC). PIM has been suggested to be a subset of condyloma associated with low-risk type human papilloma virus (HPV), however, the etiologic role of HPV and biologic behavior of the disease are still elusive. We compared the clinical and histopathological findings, immunohistochemical expression of Ki-67 and p53 protein, and HPV typing of 5 cases of PIM with SM (n=9), HSIL (n=6), and PSC (n=4) to know the helpful features for the differential diagnosis. Histologically, all 5 cases showed a papillary proliferation of immature metaplastic cells involving the proximal transformation zone and endocervix. On HPV typing by polymerase chain reaction-restriction fragment length polymorphism, 2 out of 5 PIM were confirmed to have HPV 6 or HPV 11, while 2 out of 4 PSC were proved having HPV 31 and HPV 16 each. Ki-67 labeling index and mitotic index of PIM were significantly lower than those of HSIL or PSC. There were no significant differences of Ki-67 labeling index and mitotic index between PIM and SM. The expression of p53 varied among the groups and thus it was not helpful for the differential diagnosis.
Adult ; Carcinoma in Situ/*pathology ; Carcinoma, Papillary/*pathology ; Carcinoma, Squamous Cell/*pathology ; Cervix Neoplasms/*pathology ; DNA, Viral/analysis ; Diagnosis, Differential ; Epithelial Cells/chemistry/pathology ; Female ; Follow-Up Studies ; Human ; Ki-67 Antigen/analysis ; Papillomavirus/genetics ; Papillomavirus Infections/pathology ; Protein p53/analysis ; Tumor Virus Infections/pathology ; Vaginal Smears

Over 60 different types of human papillomavirus (HPV) have been identified, and they are classified into high and low risk groups based on the risk for malignant progression of HPV associated lesions. HPVs belonging to a high risk group have been shown to express two major transforming proteins, E6 and E7. With respect to the transforming activity of these proteins, many investigators have reported the location of these proteins in the cell, but their results are still controversial. In the present study, HPV type 16 E6 or E7 open reading frame (ORF) proteins were expressed and localized in human epidermal keratinocytes (RHEK-1) using the vaccinia virus as an expression vector. Immunofluorescence detection using monoclonal antibodies against E6 or E7 ORF proteins revealed that E6 or E7 proteins of HPV type 16 were located in the cytoplasm of RHEK-1 cells. These results suggest that E6 and E7 proteins bind to the tumor suppressor counterparts, thereby preventing transport of these proteins into the nucleus. These antioncogene products that fail to be rapidly transported out of the cytosol may be degraded by certain proteases such as the ubiquitin dependent system. In this way, the precise function of antioncogene products in the regulation of cell growth could be destroyed, and abnormal cell growth could occur.
Animal ; Base Sequence ; Cell Line ; Fluorescent Antibody Technique ; Haplorhini ; Human ; Keratinocytes/metabolism ; Molecular Sequence Data ; Oncogene Proteins, Viral/*biosynthesis ; Open Reading Frames/*physiology ; Papillomavirus, Human/*chemistry ; Plaque Assay ; Polymerase Chain Reaction ; Recombinant Proteins/biosynthesis ; Support, Non-U.S. Gov't ; Vaccinia virus/genetics