ABSTRACT
Introducción: Infección persistente con el virus de papiloma humano de alto riesgo (VPH-AR) causa cáncer de cuello uterino (CCU). Existen ensayos moleculares para la detección y la genotipificación del gen L1 de VPH, sin embargo, L1 puede perderse durante la integración viral. La expresión e integración del oncogén E7 es fundamental para el desarrollo de CCU. Objetivo: Estandarizar una PCR multiplex (mPCR) del oncogén E7 (E7-mPCR) para genotipificación de los VPH-AR de mayor frecuencia en CCU (VPH-16, -18, -31, -33, -45 y -52). Métodos: Se obtuvieron cepillados cervicales de voluntarias y se analizaron amplificando por PCR el gen L1 con subsecuente hibridación reversa. Posteriormente, se escogieron 59 muestras positivas para VPH-AR y se analizaron por E7-mPCR. Resultados: Se evidenció una elevada concordancia entre los resultados del ensayo E7- mPCR y los de la PCR de L1 (concordancia observada de 95,1%, Kappa de Cohen = 0,88), encontrándose mayor número de infecciones por VPH- AR en el 15,8% con E7-mPCR. Conclusión: E7-mPCR es una herramienta diagnóstica con alta concordancia y económica que puede adaptarse a una plataforma de mayor complejidad para procesar y detectar mayor cantidad de muestras y genotipos de VPH-AR.
Introduction: The persistent infection of the high-risk Human Papiloma Virus (VPH-AR in Spanish) causes uterine cervix cancer (CCU in Spanish). There are molecular essays for detection and genotyping of gen L1 of VPH. However, L1 may get lost during the viral integration. The expression and integration of oncogene E7 is fundamental for the development of CCU. Objective: To standardize a multiplex PCR (mPCR) of oncogene E7 (E7-mPCR) for genotyping the VPH- AR of highest frequency in CCU (VPH-16, -18, -31, -33, -45 y -52). Method: We obtained cervix brushing simples from volunteers and we analyzed them by amplifying the L1 gene through PCR with a subsequent reverse hybridization. After that, we chose 59 positive VPH- AR samples and we analyzed them for E7-mPCR. Results: We found out a high concordance between the results of the essay E7-mPCR and those of L1 PC (Observed concordance was of 95.1%, Cohen's Kappa = 0.88), and we revealed a higher number of infections for VPH-AR in a 15.8% with E7-mPCR. Conclusion: E7-mPCR is an economic diagnostic tool with high concordance which can be adapted to a platform with more complexity to process and detect a higher number of samples and VPH-AR genotypes.
Introdução: a infecção persistente com o virus de papiloma humano de alto risco (HPV-AR) causa cáncer de colo do útero (CCU). Existem ensaios moleculares para detecção e para a genotipificação do gene L1 de HPV; contudo, L1 pode ser perdido durante a integrado viral. A expressão e integração do oncogênese E7 é fundamental para o desenvolvimento do CCU. Objetivo: padronizar uma PCR multiplex (mPCR) do oncogênese E7 (E7-mPCR) para genotipificação dos HPV-AR de maior frequência no CCU (HPV-16, -18, -31, -33, -45 e -52). Métodos: foram realizadas raspagens com escova cervical rodada em voluntárias e foram analisadas a partir da amplificação do gene L1 por PCR com subsequente hibridação inversa. Em seguida, foram escolhidas 59 amostras positivas para HPV-AR, as quais foram analisadas por E7-mPCR. Resultados: foi evidenciada elevada concordância entre os resultados do ensaio E7-mPCR e os da PCR de L1 (concordância observada de 95,1%, Kappa de Cohen = 0,88), encontrando-se maior número de infecções por HPV-AR em 15,8% com E7-mPCR. Conclusão: E7-mPCR é uma ferramenta diagnóstica com alta concordância e económica que pode ser adaptada a uma plataforma de maior complexidade para processar e detectar maior quantidade de amostras e genótipos de HPV-AR.
ABSTRACT
Objective To construct recombinant plasmids containing HPV18E7 gene ,and explore the optimization condition of its expression in Escherichia coli .Methods The genomic DNA extracted from HeLa cell line which served as a template to the HPV18 E7 gene was amplified using PCR method ;and the amplified product of HPV18E7 gene was connected to the pET-32a(+ ) vector ,which composed the pET-32a(+ )-HPV18E7 recombinant plasmid ;the positive recombinant plasmids were transformed into BL21-DE3-pLysS competent cells and the optimized expression condition was explored in order to obtain a large amount of HPV18E7 oncogenic protein .Results The fragment length of PCR products of HeLa cell genomic DNA was consistent with that of HPV18 E7 gene .In LB medium ,the expression level of the target protein was not high under such conditions as different concentra-tion of IPTG and lactose ,different temperatures and different induction starting amount .Therefore the ZYM-5052 auto-induction medium was tried in this experiment ,and the expression amount of the fusion protein was much higher than that induced with IPTG and lactose .Conclusion The amount of HPV18E7 fusion protein in ZYM-5052 automatic induction medium is much higher than that induced with IPTG and lactose .
ABSTRACT
The effects of nanometer realgar suspension on proliferation and apoptosis of human uterine cervix cancer cell line SiHa cells and oncogenic genes HPV16E6/E7 were investigated. A "micro-jet efflux" strategy was used for the preparation of nanometer realgar suspension. SiHa cells were treated with nanometer Realgar suspension in various concentrations (6.25,12.5,25 and 50mg/L) for different durations (12,24,48 and 72h). The inhibitive effect of nanometer realgar suspension on growth of SiHa cells was detected by MIT method. Special morphological changes of apoptosis were observed by transmission electron microscopy (TEM) and DNA fragments electrophoresis. The apoptotic rate was quantified by flow cytometry (FCM). The expression of HPV16E6/E7 mRNA and protein was assayed by RT-PCR and Western blot respectively. The results showed after being treated with 25-50mg/L nanometer realgar suspension for 48h, the survival rate of SiHa cells was decreased, and apoptotic rate markedly increased in a time- and concentration-dependent manner. TEM and DNA electrophoresis revealed the special morphological changes of apoptosis. The apoptotic rate of SiHa cells treated with nanometer realgar suspension was significantly higher than in the control group (P<0.01), and G0/G1 phase arrest appeared following treatment with nanometer realgar suspension in 25 and 50mg/L for 48h.RT-PCR and Western blot assay indicated that nanometer realgar suspension reduced the HPV16E6/E7 gene expression. Nanometer realgar suspension could inhibit the proliferation and induce apoptosis of SiHa cells. The mechanism may be related to the down-regulation of the HPV16E6/E7 gene expression.
ABSTRACT
OBJECTIVE: L and E6/E7 gene amplification analyses were compared to identify human papillomavirus (HPV) infection and verify the HPV type, with the intent to minimize HPV typing errors. METHODS: L1 gene verified HPV typing was accomplished via polymerase chain reaction (PCR) and membrane assays. Verification of HPV typing via E6/E7 genes was accomplished through nested multiplexed PCR. The results from 104 samples were compared. RESULTS: The rates of accordance and difference were 35% and 65%, respectively. For 29% of the analyses, nested multiplexed PCR was more diversified than the membrane assay. CONCLUSION: HPV can be classified into low-risk HPV and high-risk HPV groups. In parallel amplifications of the L and E genes is more efficient for accurate diagnosis in light of the different symptoms and attendant precautions of the risk groups.
Subject(s)
Humans , Gene Amplification , Light , Membranes , Polymerase Chain ReactionABSTRACT
OBJECTIVE: L and E6/E7 gene amplification analyses were compared to identify human papillomavirus (HPV) infection and verify the HPV type, with the intent to minimize HPV typing errors. METHODS: L1 gene verified HPV typing was accomplished via polymerase chain reaction (PCR) and membrane assays. Verification of HPV typing via E6/E7 genes was accomplished through nested multiplexed PCR. The results from 104 samples were compared. RESULTS: The rates of accordance and difference were 35% and 65%, respectively. For 29% of the analyses, nested multiplexed PCR was more diversified than the membrane assay. CONCLUSION: HPV can be classified into low-risk HPV and high-risk HPV groups. In parallel amplifications of the L and E genes is more efficient for accurate diagnosis in light of the different symptoms and attendant precautions of the risk groups.
Subject(s)
Humans , Gene Amplification , Light , Membranes , Polymerase Chain ReactionABSTRACT
Template direct dye-terminator incorporation with fluorescence-polarization (TDI-FP assay) is a technology for genotyping single nucleotide polymorphisms (SNPs). To apply this method in analyses of A647G variation in human papillomavirus (HPV) 16 E7 gene from HPV 16-positive cervical tissues, a total of 91 and 49 HPV 16-positive DNA samples obtained from women with cervical cancer and normal/inflamed cervices living in Shaanxi in northwest China were subjected to the partial E7 gene PCR with nucleotide (nt) 647 in the products. Then, the oligonucleotide probe designed to anneal immediately to nt 647 was hybridized to the template within the PCR amplicons, and extended specifically by TAMRA-ddTTP or R110-ddCTP directed by the base at nt 647. The increasing FP values were read and the base at nt 647 was identified. The prevalence of nt 647 A→G was 35.71% (50/140). The variation 647G detected in 42.86% (39/91) of women with cervical cancer was significantly higher than 22.45% (11/49) detected in those with normal/inflamed cervices (x2 = 5.778, P = 0.016). The odds ratio (OR) between these two groups was 2.59 (95% confidence interval=l.17～5.71). The results demonstrate that TDI-FP method can be potentially applied in analysis of interest point mutations in HPVs. The incidence and risk implication of HPV 16 A647G variant infection in Shaanxi, China, displays significant geographic difference from other areas. The HPV 16 with E7 gene A647G point mutation appears to have a higher risk for invasive cervical cancer in women living in Shaanxi.
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Objective To investigate the gene sequence and mutations of human papillomavirus(HPV)type16E6E7in patients with HPV infection in Beijing.Methods Sample DNA was extracted from lesions in patients with HPV infection.HPV types were identified by polymerase chain reaction(PCR).E6E7gene,isolated from samples infected with HPV16only,was cloned into plasmid pGEM-3zf and sequenced.Results The recombinant plasmid pGEM/16E6E7was constructed successfully.The whole HPV E6E7gene was776bp in length which was equal to that of the standard strain.Three nucleotides exchanges,i.e.,p60PROE6,p96GLUE6,p565SERE7,were found in E6E7gene.Conclusion The data suggest that there are nucleotide differences of HPV E6E7gene between HPV obtained from Beijing and that of standard sequence.
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Objective To construct an expression plasmid of human papillomavirus type 11 E7 (HPV11-E7)/hurnan IFN?-2b fusion gene, to express the fusion gene in E.coli BL21, and pave way for further immunological study. Methods The recombinant plasmid was introduced into E.coli BL21, then the expression product was analyzed by SDS-PAGE and Western blotting after induction with isopropy-?-D-thiogalactoside (IPTG). Results The fusion gene of HPV11-E7 and human IFN?-2b was successfully cloned into pET-32a by a linker with the same sequence as we expected. The expressed fusion protein was confirmed by SDS-PAGE and Western blotting. Conclusions The successful construction of prokaryotic expression plasmid and expression of HPV11-E7/human IFN?-2b fusion gene enable further immunological study.
ABSTRACT
Human papillomavirus (HPV)infection are now generally accepted as the most important factor for development of uterine cervical cancer and its precursor lesions. With increasing evidences that the HPV E7 encodes for oncoproteins critical for viral replication, host cell immortalization and transformation. Based on the previous reports that the high risk HPV type 16 DNA is frequently detected in specimens from Korean women with cervical cancer and that there is the sequence variation and geographical dependence of HPV 16 E7 gene in preinvasive and invasive cervical lesions, it is crucial to determine the prevalence of HPV 16 variants in uterine cervical lesions of Korean women. This study was performed to identify sequence variations of HPV 16 E7 gene and an association between HPV 16 E7 variants and uterine cervical cancer. The author has determined nucleotide sequences of the E7 gene of HPV 16 isolated from uterine cervical tissues in Korean women. HPV 16 DNAs were detected by the nested PCR in 112 (24.5%) of a total of 457 samples. By direct sequencing of PCR-HPV 16 E7 positive cases, 79 samples (70.5%) showed variant sequences, while the prototype sequence was found in only 33 samples (29.5%). Twenty-three cases (57.5%) of 40 normal cervical samples showed sequence variation. Forty-eight (77.4%) of 62 cervical cancer cases showed sequence diversity from prototype HPV 16 E7 gene. There were four types of sequence variations. A single nucleotide change at position 647 (A-->G) was found in 52 cases (65.8%) of 79 HPV 16 E7 variants. Predicted amino acid change (Asn -->Ser) was found in the HPV 16 E7 oncoproteins at amino acid position at 29. And this KE7-1 variant was commonly detected in the uterine cervical cancer compared to the normal cervix. The second most common variant, detected in 16 cases (20.3%), had three silent mutations at nucleotide positions 732 (T-->C), 789 (T-->C) and 795 (T-->G). The third variant had a single nucleotide change at position 666 (G-->A), and the fourth had a change at position 796 (T-->C). Furthermore, PCR-SSCP clearly showed distinct bands compatible with HPV 16 E7 variants as with the direct-sequencing method. PCR-SSCP was also an effective and reliable tool in detecting HPV 16 E7 variants. This study showed that there were four variant types of HPV 16 E7 in uterine cervical tissues and KE7-1 with corresponding amino acid change was the most commonly detected type in E7 variants of HPV 16 isolated from uterine cervical cancer in Korean women.