Expression Status of p16 Protein Is Associated with Human Papillomavirus Oncogenic Potential in Cervical and Genital Lesions

The p16 protein (p16) is a cyclin-dependent kinase (CDK) inhibitor that decelerates the cell cycle by inactivating the CDKs that phosphorylate retinoblastoma (Rb) protein. Recent biological studies have revealed that p16 expression is markedly influenced by the status of Rb expression, and p16 overexpression has been demonstrated in cervical cancers because of functional inactivation of Rb by human papillomavirus (HPV) E7 protein. To clarify the relationship between p16 overexpression and HPV infection in cervical carcinogenesis, immunohistochemical analysis of p16 and detection of HPV by in situ hybridization and polymerase chain reaction were performed on 139 formalin-fixed and paraffin-embedded samples of cervical and genital condylomatous and neoplastic lesions. Marked overexpression of p16 protein, ie, diffuse and strong immunostaining, was observed in all cervical cancers and preneoplastic lesions with infection by high- and intermediate-risk HPVs, ie, subtypes 16, 18, 31, 33, 52, and 58. Condylomata acuminata and low-grade squamous intraepithelial lesions with infection by low-risk HPV such as HPV-6/11 showed focal and weak immunohistochemical staining for p16. Our results clearly showed that the mode of p16 expression in lesions with high- and intermediate-risk HPVs differed from its expression in lesions with low-risk HPVs and thus might be attributable to differences in functional inactivation of Rb protein by different HPVs.     

Is Human Papillomavirus Associated with Prostate Cancer Survival?

The role of human papillomavirus (HPV) in prostate carcinogenesis is highly controversial: some studies suggest a positive association between HPV infection and an increased risk of prostate cancer (PCa), whereas others do not reveal any correlation. In this study, we investigated the prognostic impact of HPV infection on survival in 150 primary PCa patients. One hundred twelve (74.67%) patients had positive expression of HPV E7 protein, which was evaluated in tumour tissue by immunohistochemistry. DNA analysis on a subset of cases confirmed HPV infection and revealed the presence of genotype 16. In Kaplan-Meier analysis, HPV-positive cancer patients showed worse overall survival (OS) (median 4.59 years) compared to HPV-negative (median 8.24 years, P = 0.0381). In multivariate analysis age (P < 0.001), Gleason score (P < 0.001), nuclear grading (P = 0.002), and HPV status (P = 0.034) were independent prognostic factors for OS. In our cohort, we observed high prevalence of HPV nuclear E7 oncoprotein and an association between HPV infection and PCa survival. In the debate about the oncogenic activity of HPV in PCa, our results further confirm the need for additional studies to clarify the possible role of HPV in prostate carcinogenesis.     

Multiple Skin Cancers in a Renal Transplant Recipient: A Patient Report with Analyses of Human Papillomavirus and Human Polyomavirus Infection

Skin cancer is an important complication in renal transplant recipients. Associations of transplant-related skin tumor with ultraviolet radiation, age at transplantation, type of immunosuppressant drug administered, and viral infection have been reported; however, the details remain unclear. We report a 61-year-old man who had underwent renal transplantation at 38 years of age and developed multiple skin tumors or squamous cell carcinomas (SCCs). Polymerase chain reaction (PCR) analyses of the patient’s 12 tumors for viral DNAs of cutaneous or mucosal human papillomavirus (HPV) and 6 human polyomaviruses (MCPyV, trichodysplasia spinulosa-associated, BK, JC, KI and WU polyomaviruses) only detected cutaneous HPV-DNA in only 5 of the tumors; no other viruses were detected. Real-time PCR showed high loads of cutaneous HPV in 3 SCCs and very low loads of MCPyV in 9. Immunohistochemistry revealed no tumor cell expression for MCPyV-large T-antigen or mucosal HPV. Our report not only reconfirmed the association of cutaneous HPV5 with skin cancer in renal transplant recipients in previous studies but also showed no relevant association of 6 human polyomaviruses and mucosal HPV with skin tumors.     

人乳头瘤病毒16 E6蛋白单克隆抗体的研制

运用杂交瘤技术，我们成功地建立了两株能稳定分泌小鼠抗人乳头瘤病毒１６Ｅ６蛋白单克隆抗体的杂交瘤细胞。经鉴定单克隆抗体均属ＩｇＧ１ｋ。试验结果表明，所得单克隆抗体仅与ＨＰＶ１６Ｅ６融合蛋白反应，不与ＨＰＶ１６Ｅ７、Ｌ１、Ｌ２融合蛋白以及Ｌ１－Ｌ２真核表达蛋白反应，也只与Ｃａｓｋｉ细胞反应，不与Ｈｅｌａ细胞反应。初步结果说明，该抗体是ＨＰＶ１６Ｅ１６蛋白特异性的ＭｃＡｂ。     

原核表达系统中 HPV16 L1蛋白的表达与纯化

为了建立HPV16L1蛋白原核表达系统系统的纯化方法，纯化目的蛋白，我们构建了pGEX4T-HPV16L1表达质粒。在大肠杆菌BL21表达系统中表达，经过包涵体提取，8M尿素溶解，分级透析除去尿素，亲和层析进行提纯。结果,HPV16L1蛋白在原核表达系统以不溶性包涵体形式存在，通过本病方法可以获得纯化的HPV16L1蛋白，为HPV16L1的应用研究打下了基础。     

A Unique Verrucous Anogenital Tumor Associated with Type 6b-related Human Papillomavirus

Multilpe dark brown papillomatous tumors, showing some histological features of verrucous carcinoma or giant condyloma, developed mainly in the anogenital region of a Japanese woman. The tumors first appeared when she was 51 years old and annoyed her for over 20 years with several recurrences without any frank malignant trasformation, after surgery. Immunohistochemically, papillomavirus genus-specific antigen was demonstrated only in small foci of the lesions resected at first operation. Southern blot analysis revealed human papillomavirus type 6b-related DNA in a surgically resected specimen. The possible role of the human papillomavirus in the genesis of this unique tumor is discussed. Acta Pathol. Jpn. 39: 528∼532, 1989.     

Expression Pattern and Subcellular Localization of Human Papillomavirus Minor Capsid Protein L2

The expression pattern of human papillomavirus (HPV) capsid antigen L2 is poorly described, and the significance of its localization with both promyelocytic leukemia protein (PML) and Daxx in a subnuclear domain, nuclear domain 10 (ND-10), when ectopically expressed in tissue culture cells is controversial. To address whether ND-10 localization of L2 occurs in natural cervical lesions, we used a HPV16 and HPV18 L2-specific monoclonal antibody (RG-1), in addition to rabbit antiserum to HPV6 L2, to localize L2. Immunohistochemical staining with RG-1 produced diffuse staining in the nuclei of some cells located within the superficial epithelial layers in eight of nine cases of HPV16/18⁺ cervical intraepithelial neoplasia grade 1 (CIN1); however, no staining was observed in HPV16/18⁺ high-grade CIN (0 of 8 cases), normal cervical epithelium (0 of 20 cases), cervical squamous cell carcinoma (0 of 102 cases), adenocarcinoma (0 of 51 cases), or adenosquamous carcinoma (0 of 6 cases). HPV16/18⁺ cervical lesions that express L2 exhibit higher HPV16/18 genome copies per cell compared with those that do not positively stain with RG-1 (P = 0.04). RG-1 staining of HeLa cells transfected with L2 expression constructs was frequently concentrated in the ND-10, particularly in cells expressing high levels of L2, and co-localized with the cellular markers of ND-10, PML, and Daxx. In contrast, L2 was primarily diffuse within the nucleus and distinct from ND-10 as defined by PML immunofluorescent staining in CIN lesions, condylomata, and HPV16-transduced organotypic cultures.     

Analysis by Multiplex PCR of the Physical Status of Human Papillomavirus Type 16 DNA in Cervical Cancers

Integration of human papillomavirus (HPV) DNA occurs early in cancer development and is an important event in malignant transformation of cervical cancer. Integration of HPVs preferentially disrupts or deletes the E2 open reading frame, which results in the loss of its expression. The preferential disruption of the E2 gene causes the absence of the E2 gene sequences in the PCR product following integration. Twenty-two carcinomas positive for HPV type 16 (HPV-16) DNA were first tested for the disruption of the E2 gene by PCR. A specific fragment of the E2 gene was not amplified in 10 cases, suggesting integration of HPV DNA into the host genome. Next, multiplex PCR for the HPV E2 and E6 genes was carried out in the remaining 12 cases. Copy numbers of both genes should be equivalent in episomal forms, while the E2 gene copy number will be smaller than that for E6 following the preferential disruption of the E2 gene in concomitant forms. Although relative ratios of HPV E2 to E6 PCR products (E2/E6 ratios) ranged from 1.40 to 2.34 in 10 of 12 cases, multiplex PCR products from 2 cases displayed extremely low ratios of 0.69 and 0.61. Southern blot hybridization with an HPV-16 probe revealed that only in these two cases was both episomal and integrated HPV DNA being carried simultaneously. Thus, multiplex PCR for the E2 and E6 genes of HPV-16 DNA following PCR for the E2 gene can distinguish the pure episomal form from a mixed form of episomal and integrated HPV DNA. Clinical application of this technique will help researchers to understand the implication of the integration of HPV DNA for cervical carcinogenesis and cervical cancer progression.     

Immunological Characterization of a Modified Vaccinia Virus Ankara Vector Expressing the Human Papillomavirus 16 E1 Protein

Women showing normal cytology but diagnosed with a persistent high-risk human papillomavirus (HR-HPV) infection have a higher risk of developing high-grade cervical intraepithelial neoplasia and cervical cancer than noninfected women. As no therapeutic management other than surveillance is offered to these women, there is a major challenge to develop novel targeted therapies dedicated to the treatment of these patients. As such, E1 and E2 antigens, expressed early in the HPV life cycle, represent very interesting candidates. Both proteins are necessary for maintaining coordinated viral replication and gene synthesis during the differentiation process of the epithelium and are essential for the virus to complete its normal and propagative replication cycle. In the present study, we evaluated a new active targeted immunotherapeutic, a modified vaccinia virus Ankara (MVA) vector containing the E1 sequence of HPV16, aimed at inducing cellular immune responses with the potential to help and clear persistent HPV16-related infection. We carried out an extensive comparative time course analysis of the cellular immune responses induced by different schedules of immunization in C57BL/6 mice. We showed that multiple injections of MVA-E1 allowed sustained HPV16 E1-specific cellular immune responses in vaccinated mice and had no impact on the exhaustion phenotype of the generated HPV16 E1-specific CD8⁺ T cells, but they led to the differentiation of multifunctional effector T cells with high cytotoxic capacity. This study provides proof of concept that an MVA expressing HPV16 E1 can induce robust and long-lasting E1-specific responses and warrants further development of this candidate.     

Molecular Cloning and Nucleotide Sequence Analysis of a Novel Human Papillomavirus (Type 82) Associated with Vaginal Intraepithelial Neoplasia

The genome of a novel human papillomavirus (HPV-82) was cloned from a vaginal intraepithelial neoplasia grade I. In our series of 291 biopsy specimens, HPV-82 was identified in one case each of cervical intraepithelial neoplasia grade II and grade III by blot hybridization. The histological localization of HPV-82 DNA in the three lesions was confirmed by in situ hybridization. The results indicated that HPV-82 is an etiologic agent for vaginal and cervical intraepithelial neoplasia. By nucleotide sequence similarity of L1 open reading frame (ORF), HPV-82 was closely related to HPV-26, -51, and -69. To know the precise relationship between the HPVs, we determined the complete sequence of HPV-82, as well as that of HPV-69. Sequencing revealed that the four HPVs had no initiation codon in the E5 ORF and had extensive nucleotide sequence similarities in all ORFs. In addition, they exhibited unique frame position patterns for ORFs, different from those of the other genital HPVs.     

Development of a National Agreement on Human Papillomavirus Vaccination in Japan: An Infodemiology Study

Background

A national agreement on human papillomavirus (HPV) vaccination was achieved relatively quickly in Japan as compared to the United States and India.

Objective

The objective was to identify the role of print and online media references, including references to celebrities or other informants, as factors potentially responsible for the relatively rapid national acceptance of HPV vaccination in Japan.

Methods

A method of text mining was performed to select keywords, representing the context of the target documents, from articles relevant to the promotion of HPV vaccination appearing in major Japanese newspapers and Web pages between January 2009 and July 2010. The selected keywords were classified as positive, negative, or neutral, and the transition of the frequency of their appearance was analyzed.

Results

The number of positive and neutral keywords appearing in newspaper articles increased sharply in early 2010 while the number of negative keywords remained low. The numbers of positive, neutral, and negative keywords appearing in Web pages increased gradually and did not significantly differ by category. Neutral keywords, such as “vaccine” and “prevention,” appeared more frequently in newspaper articles, whereas negative keywords, such as “infertility” and “side effect,” appeared more frequently in Web pages. The extraction of the positive keyword “signature campaign” suggests that vaccine beneficiaries cooperated with providers in promoting HPV vaccination.

Conclusions

The rapid development of a national agreement regarding HPV vaccination in Japan may be primarily attributed to the advocacy of vaccine beneficiaries, supported by advocacy by celebrities and positive reporting by print and online media.     

Heterochromatin Protein 1γ Epigenetically Regulates Cell Differentiation and Exhibits Potential as a Therapeutic Target for Various Types of Cancers

Heterochromatin protein 1 (HP1) is a chromosomal protein that participates in both chromatin packaging and gene silencing. Three HP1 isoforms (α, β, and γ) occur in mammals, but their functional differences are still incompletely understood. In this study, we found that HP1γ levels are decreased during adipocyte differentiation, whereas HP1α and β levels are expressed constitutively during adipogenesis in cultured preadipocyte cells. In addition, ectopic overexpression of HP1γ inhibited adipogenesis. Furthermore, we did not detect any HP1γ protein in the differentiated cells of various normal human tissues. These results suggest that the loss of HP1γ is required for cell differentiation to occur. On the other hand, the methylation levels of lysine 20 (K20) on histone H4 showed a significant correlation with HP1γ expression in both these preadipocyte cells and normal tissue samples. However, all cancer tissues examined were positive for HP1γ but were often negative for trimethylated histone H4 K20. Thus, a dissociation of the correlation between HP1γ expression and histone H4 K20 trimethylation may reflect the malfunction of epigenetic control. Finally, suppression of HP1γ expression restrained cell growth in various cancer-derived cell lines, suggesting that HP1γ may be an effective target for gene therapy against various human cancers. Taken together, our results demonstrate the novel function of HP1γ in the epigenetic regulation of both cell differentiation and cancer development.     

人乳头瘤病毒16型变异株E7蛋白在HeLa细胞中的表达及亚细胞定位

目的构建增强绿色荧光蛋白(EGFP)-人乳头瘤病毒16型变异株E7(HPV16-HBE7)重组质粒pEGFP-HBE7,研究HPV16-HBE7蛋白亚细胞定位,为进一步了解其生物学功能奠定基础。方法采用分子克隆技术,将HPV16-HBE7基因克隆在pEGFP-C1表达载体上,用脂质体法导入宫颈癌细胞中;West-ern印迹检测HBE7蛋白的表达;同时借助免疫荧光技术和EGFP-融合蛋白技术,采用激光共聚焦显微镜观察HBE7蛋白的亚细胞定位。结果重组质粒经PCR、酶切和测序鉴定,其目的片段大小、插入位点和核苷酸序列完全正确;结果表明,转染细胞HBE7蛋白的相对表达量其胞浆明显多于胞核;各个时间段HBE7蛋白均以胞浆分布为主,绿色荧光密集点状分布于细胞浆内,而野生株E7(WE7)蛋白分布在核内。结论人乳头瘤病毒16型变异株E7蛋白主要分布在细胞浆内,以胞浆为主的分布可能和HBE7基因发生突变后丢失核定位信号有关。     

Human MHC Class I Antigens are Associated with a 90-kDa Cell Surface Protein

Human MHC class I proteins are expressed on almost all nucleated cells as a heavy chain (about 45 kDa) non-covalently associated with beta 2-microglobulin (12 kDa). In this report we show that MHC class I (MHC-I) proteins can also be associated with a 90-kDa protein in the cell membrane. Surface-radiolabelled cells were treated with dithiobis succinimidyl propionate (DSP) in order to preserve multimer protein complexes during cell lysis. The lysates were immunoprecipitated and analysed by SDS-PAGE and autoradiography. Immunoprecipitation of human MHC-I proteins co-precipitated another protein of about 90 kDa in molecular weight-p90. p90 was coprecipitated from all the MHC-I expressing cells tested: U937, Raji, Molt-4 and IFN-gamma treated K562, but not from untreated, MHC-I negative K562. A 90-kDa protein was also co-precipitated with MHC-I from fresh peripheral blood mononuclear cells (PBMC). Furthermore, p90 was coprecipitated by different MoAbs to the MHC-I heavy chain or beta 2-microglobulin, but not by control antibodies. Two additional co-precipitating proteins at 34 kDa and 28 kDa were seen in MHC-I precipitates from Raji cells. Our results suggest that MHC-I proteins and the 90-kDa protein are associated in the cell membrane, probably by a close but weak, non-covalent interaction. Two additional cell surface proteins at 34 kDa and 28 kDa seem to be MHC-I associated on Raji Burkitt's lymphoma cells.