YAP1-LATS2 feedback loop dictates senescent or malignant cell fate to maintain tissue homeostasis.

Dysfunction of the homeostasis-maintaining systems in specific cell types or tissues renders the organism susceptible to a range of diseases, including cancers. One of the emerging mechanisms for maintaining tissue homeostasis is cellular senescence. Here, we report that the Hippo pathway plays a critical role in controlling the fate of ovarian cells. Hyperactivation of Yes-associated protein 1 (YAP1), the major effector of the Hippo pathway, induces senescence in cultured primary human ovarian surface epithelial cells (hOSEs). Large tumor suppressor 2 (LATS2), the primary upstream negative regulator of YAP1, is elevated in both YAP1-induced and natural replicative-triggered senescence. Deletion of LATS2 in hOSEs prevents these cells from natural replicative and YAP1-induced senescence. Most importantly, loss of LATS2 switches ovarian cells from YAP-induced senescence to malignant transformation. Our results demonstrate that LATS2 and YAP1, two major components of the Hippo/YAP signaling pathway, form a negative feedback loop to control YAP1 activity and prevent ovarian cells from malignant transformation. Human cancer genomic data extracted from TCGA datasets further confirm the clinical relevance of our finding.

Analytical performance of a low-cost multiplex polymerase chain reaction human papillomavirus genotyping assay for use in Sub-Saharan Africa.

We have tested a multiplex polymerase chain reaction (PCR) human papillomavirus (HPV) genotyping assay to fill the need for rapid and low-cost HPV detection in Sub-Saharan Africa. This method allows high throughput genotyping and simultaneous detection of 14 high-risk and two low-risk HPV types, by PCR amplification of HPV DNAs in a single reaction tube. In this study, we describe stepwise experiments to validate the multiplex HPV PCR assay for determination of HPV genotypes from 104 cervical brush samples from Tanzanian women. Assay performance was evaluated by determination of intra-laboratory reproducibility, sensitivity, and specificity. Further performance was assessed by comparison with the widely accepted and validated HPV My09/My11 amplification and hybridization assay. Statistics; the Cohen kappa (κ) and McNemar P values were used to analyze interobserver and intermethod agreement. Overall concordance between the multiplex and line blot hybridization assays was 99% (per sample) with a κ value equal to 0.95; and 96.49% (per detection event) with a κ value of 0.92. Interobserver reproducibility of the assay per sample was 95.76% with κ of 0.91. These results demonstrate that the multiplex HPV PCR assay has high analytical sensitivity and specificity in detecting as many as 16 different HPV genotypes and that its simplicity and low cost makes it well suited for sub-Saharan Africa.

Investigating the Physiological Mechanisms between Resistance Training and Pain Relief in the Cancer Population: A Literature Review.

This literature review examines the mechanisms of how exercise, specifically in the form of resistance training, may lead to pain relief in the cancer population. Primary data from three different cancer populations: breast, prostate, and lung, will be examined. A number of experimental studies have been conducted to confirm the effectiveness of resistance training on pain relief as well as the biochemical pathways that relate to this process. In this review, we will examine 5 randomized controlled trials. For the purposes of this review, pain is defined as physical suffering or discomfort associated with illness. Pain is the body's natural signal, bringing attention to damage that has been sustained by tissues. However, chronic pain is common in the cancer population, and often serves no good purpose but instead will negatively impact both physical and mental health. The three types of pain: nociceptive, neuropathic, and inflammatory pathways have been investigated, and the knowledge of pain mechanisms allows for the understanding of how it is associated with pain. The purpose of this exploratory literature review is to give insight on how to maximize pain-relieving effects of resistance training. Research has indicated that resistance training modulates pain pathways by upregulating the release of pain-relieving substances including beta-endorphins, anti-inflammatory cytokines, and endocannabinoids. Understanding of the benefits of resistance training may be useful in relieving cancer pain, and reproducing effects of pain-relieving strategies while minimizing the symptoms related to cancer and its treatment.

Yes-associated protein-1 overexpression in ocular surface squamous neoplasia; a potential diagnostic marker and therapeutic target.

Yes-associated protein-1 (YAP-1) is a Hippo system transcription factor, which serves as an oncogene in squamous cell carcinoma, and several solid tumors when the Hippo pathway is dysregulated. Yet, the activity of YAP-1 in ocular surface squamous neoplasia (OSSN) has not been determined. Here, we investigate the relationship between YAP-1 overexpression and OSSN. Using a cross-sectional study design, we recruited 227 OSSN patients from the University Teaching Hospitals in Lusaka, Zambia. Immunohistochemistry was used to assess YAP-1 protein overexpression in tumor tissue relative to surrounding benign squamous epithelium. OSSN patient samples (preinvasive, n = 62, 27% and invasive, n = 165, 73%) were studied. One hundred forty-nine invasive tumors contained adjacent preinvasive tissue, bringing the total number of preinvasive lesions examined to 211 (62 + 149). There was adjacent benign squamous epithelium in 50.2% (114/227) of OSSN samples. Nuclear YAP- 1 was significantly overexpressed in preinvasive (Fisher's (F): p <.0001, Monte Carlo (MC): p <.0001) and invasive (F: p <.0001, MC: p <.0001) OSSN in comparison to adjacent benign squamous epithelium when analyzed for basal keratinocyte positive count, staining intensity, expression pattern, and Immunostaining intensity-distribution index. YAP-1 expression did not differ between preinvasive and invasive OSSN (p >.05), keratinizing and non- keratinizing cancer (p >.05), or between T1/T2 and T3/T4 stages in invasive tumors (p >.05). However, grade 2 and 3 tumors had significantly stronger nucleus YAP-1 overexpression intensity than grade 1 tumors (F: p = .0078, MC: p = .0489). By immunohistochemistry, we identified significant overexpression (upregulation of YAP-1 protein expression) in preinvasive and invasive OSSN lesions compared to neighboring benign squamous epithelium. YAP-1 expression was significantly higher in poorly and moderately differentiated invasive squamous cancer than in well-differentiated carcinomas. Overexpression of YAP-1 within the margin of preinvasive and invasive OSSN, but not in the neighboring normal epithelium, indicates that it plays a role in the development and progression of OSSN.

Genome Sequence of Feline Papillomavirus Strain P20 Assembled from Metagenomic Data from the Skin of a House Cat Owner.

A feline papillomavirus genome was assembled from metagenomic sequencing data collected from the skin of a house cat owner. The circular genome of strain P20 is 8,069 bp in length, has a GC content of 54.38%, and displays genome organization typical of feline papillomaviruses. The genome exhibits approximately 75% sequence similarity to other feline papillomavirus genomes.

Epstein-Barr Virus, But Not Human Papillomavirus, Is Associated With Preinvasive and Invasive Ocular Surface Squamous Neoplasias in Zambian Patients.

Background: The etiopathogenesis of ocular surface squamous neoplasia (OSSN) is not fully understood. We assessed the frequency of oncogenic viruses in OSSN by immunohistochemistry (IHC) and polymerase chain reaction (PCR) for human papillomavirus (HPV), Epstein-Barr virus (EBV), Merkel cell polyomavirus (MCPyV), Kaposi sarcoma virus, and adenovirus. Cases from Zambia were prospectively enrolled using a cross-sectional study design between November 2017 and March 2020. Methods: Demographic and clinical data [age, sex, HIV status, antiretroviral therapy (ART) history, CD4 count, plasma viral load] and tumor biopsies were collected from 243 consenting patients. Tumor samples were bisected, and half was used for DNA isolation, while the other half was formalin fixed and paraffin embedded (FFPE) for histopathology analysis. The expressions of latent EBV nuclear antigen 1 (EBNA1), CDKN2A/p16INK4A (p16), and MCPyV large T-antigen (LT) were tested by IHC. Multiplex PCR was used to detect 16 HPV genotypes and four other DNA tumor viruses [Kaposi's sarcoma-associated herpesvirus (KSHV), EBV, MCPyV, and adenovirus]. Relationships between HIV status, viral DNA and protein expression, and tumor grades were determined by statistical analysis. Results: OSSN tumors from patients were 29.6% preinvasive and 70.4% invasive. Patients presented with unilateral tumors that were 70.4% late stage (T3/T4). OSSN patients were HIV positive (72.8%). IHC on 243 FFPE biopsies resulted in the detection of EBNA1 (EBV), p16 high-risk HPV (HR-HPV), and MCPyV LT expression in 89.0%, 4.9%, and 0.0%, respectively. EBNA1 was expressed in all grades of preinvasive [cornea-conjunctiva intraepithelial neoplasia (CIN)1, 100%; CIN2, 85.7%; CIN3, 95.8%; and carcinoma in situ (CIS), 83.8%] and in invasive (89.2%) OSSN. PCR on 178 samples detected EBV, HR-HPV, and MCPyV in 80.3%, 9.0%, and 13.5% of tumors, respectively. EBV was detected in all grades of preinvasive and invasive OSSN. EBV detection was associated with high HIV viral loads (p = 0.022). HR-HPV was detected in 0.0% CIN1, 0.0% CIN2, 5.6% CIN3, 13.0% CIS, and 7.0% invasive OSSN. Conclusions: Our findings of EBV DNA and EBNA1 protein in all the grades of preinvasive and especially invasive OSSN are consistent with a potential causal role for EBV in OSSN. A role of HPV in OSSN was not clearly established in this study.

Human papillomavirus 16 variants from Zambian women with normal pap smears.

Human papillomavirus (HPV) type 16 is the most prevalent high-risk viral genotype associated with cervical cancer. Six distinct phylogenetic clusters of HPVs have been identified and are distributed differently across five continents. HPV16 DNA was extracted from cervicolavage samples from women with normal pap smears. The LCR regions were amplified in triplicate, cloned, sequenced, and analyzed from a total of 11 recovered HPV16 positive samples [Ng'andwe et al. (2007): BMC Infect Dis 7:77] were analyzed for sequence variation. The HPV16 LCR variants were assessed for promoter activity by use of a luciferase reporter gene. Six novel HPV16 variants with nucleotide exchanges in the LCR region were identified. Five clones were classified as European group HPV16 variants and one as an African group variant. Two of these variants had relatively lower promoter activity, 30% of that of the wild-type strain. The decreased promoter activity of some HPV16 variants may decrease expression of viral oncogenes and may be linked with the development, phenotype and severity of the cervical lesions in women infected with these across HPV16 variants.

Evolutionary variation of papillomavirus E2 protein and E2 binding sites.

BACKGROUND: In an effort to identify the evolutionary changes relevant to E2 function, within and between papillomavirus genera, we evaluated the E2 binding sites (E2BS)s inside the long-control-region (LCR), and throughout the genomes. We identified E2BSs in the six largest genera of papillomaviruses: Alpha, Beta, Gamma, Delta, Lambda, and Xi-papillomaviruses (128 genomes), by comparing the sequences with a model consensus we created from known functional E2BSs (HPV16, HPV18, BPV1). We analyzed the sequence conservation and nucleotide content of the 4-nucleotide spacer within E2BSs. We determined that there is a statistically significant difference in GC content of the four-nucleotide E2BS spacer, between Alpha and Delta-papillomaviruses, as compared to each of the other groups. Additionally, we performed multiple alignments of E2 protein sequences using members of each genus in order to identify evolutionary changes within the E2 protein. RESULTS: When a phylogenetic tree was generated from E2 amino acid sequences, it was discovered that the alpha-papillomavirus genera segregates into two distinct subgroups (α1 and α2). When these subgroups were individually analyzed, it was determined that the subgroup α1 consensus E2BS favored a spacer of AAAA, whereas subgroup α2 favored the opposite orientation of the same spacer; TTTT. This observation suggests that these conserved inverted linkers could have functional importance.

Clinical and Pathologic Presentation of Primary Ocular Surface Tumors among Zambians.

AIM: This study aimed to characterize the clinical and pathologic presentation of ocular surface tumors (OSTs) and to more precisely differentiate the grades of ocular surface squamous neoplasia (OSSN) and benign lesions among Zambians. METHODS: Two-hundred sixty-five Zambian patients presenting with ocular surface growths, suspicious for OSSN, were recruited between November 2017 and November 2019 to a cross-sectional study to investigate their lesions. Sociodemographic data were collected, HIV infection status and vision tests were performed, and lesions were measured and documented. Lesions >2 mm in diameter were excised and sent for pathology analysis. In addition to the biopsies, tears, blood, and buccal swabs were collected. CD4+ T-cell counts were measured by flow cytometry. Lesions were classified according to the WHO guidelines. χ2 and bivariate correlations were used to analyze variable associations and strengths with phi/Cramer's V and correlation coefficients, respectively. Binary logistics was used to adjust for covariance. RESULTS: In this study, 68.3% of the participants were found to be HIV positive. The most frequent diagnoses were invasive OSSN (45.3%), preinvasive OSSN (29.1%), and pterygium (22.6%). Invasive OSSN comprised keratinizing squamous cell carcinoma (SCC) (87.5%), basaloid SCC (3.3%), and spindle cell carcinoma (3.3%). Unusual carcinomas, not described previously, included hybrid SCC (5.0%) and acantholytic SCC (0.8%). Invasive OSSN had advanced tumor (T3/T4) staging (93.3%) at diagnosis. Lymphadenopathy was rare (2.3%), and metastasis was absent. Patients were mostly female (59.2%). Median age was 36 (interquartile ranges 33-41) years (ranges 18-81). Patients with invasive OSSN were more likely to present with pain (p = 0.007), redness (p = 0.034), excessive tearing (p = 0.0001), discharge (p = 0.011), bleeding (p = 0.007), reduced vision (p = 0.0001), fungating lesion (p = 0.001), and blindness (p = 0.005); location at temporal limbus (p = 0.0001), inferior limbus (p = 0.0001), or circumlimbal (p = 0.001); and extension to cornea (p = 0.006) and forniceal palpebral conjunctiva (p = 0.001). Invasive OSSN was associated with any smoking habit and alcohol consumption (p = 0.04 and 0.03, respectively). HIV positivity was strongly associated with OSSN (74.6% OSSN vs. 49.3% benign lesions; p = 0.0001; phi: 0.237 [p = 0.0001]). CONCLUSION: OSTs are very common in Zambia and are strongly associated with HIV coinfection. Patients with OSSN were more likely to be HIV positive than those with pterygia. Despite the commonality of OSTs in sub-Saharan Africa, these cancers have historically been poorly characterized.

Viral trans-factor independent replication of human papillomavirus genomes.

BACKGROUND: Papillomaviruses (PVs) establish a persistent infection in the proliferating basal cells of the epithelium. The viral genome is replicated and maintained as a low-copy nuclear plasmid in basal keratinocytes. Bovine and human papillomaviruses (BPV and HPV) are known to utilize two viral proteins; E1, a DNA helicase, and E2, a transcription factor, which have been considered essential for viral DNA replication. However, growing evidence suggests that E1 and E2 are not entirely essential for stable replication of HPV. RESULTS: Here we report that multiple HPV16 mutants, lacking either or both E1 and E2 open reading frame (ORFs) and the long control region (LCR), still support extrachromosomal replication. Our data clearly indicate that HPV16 has a mode of replication, independent of viral trans-factors, E1 and E2, which is achieved by origin activity located outside of the LCR.

How the Cervical Microbiota Contributes to Cervical Cancer Risk in Sub-Saharan Africa.

Despite ongoing efforts, sub-Saharan Africa faces a higher cervical cancer burden than anywhere else in the world. Besides HPV infection, definitive factors of cervical cancer are still unclear. Particular states of the cervicovaginal microbiota and viral infections are associated with increased cervical cancer risk. Notably, HIV infection, which is prevalent in sub-Saharan Africa, greatly increases risk of cervicovaginal dysbiosis and cervical cancer. To better understand and address cervical cancer in sub-Saharan Africa, a better knowledge of the regional cervicovaginal microbiome is required This review establishes current knowledge of HPV, HIV, cervicovaginal infections, and the cervicovaginal microbiota in sub-Saharan Africa. Because population statistics are not available for the region, estimates are derived from smaller cohort studies. Microbiota associated with cervical inflammation have been found to be especially prevalent in sub-Saharan Africa, and to associate with increased cervical cancer risk. In addition to high prevalence and diversity of HIV and HPV, intracellular bacterial infections such as Chlamydia, Gonorrhea, and Mycoplasma hominis are much more common than in regions with a low burden of cervical cancer. This suggests the prevalence of cervical cancer in sub-Saharan Africa may be partially attributed to increased cervical inflammation resulting from higher likelihood of cervical infection and/or microbial dysbiosis.

Mycoplasma Co-Infection Is Associated with Cervical Cancer Risk.

Tanzania faces one of the highest cervical cancer burdens in the world. Recent work has suggested that the bacterial family Mycoplasmataceae is associated with higher levels of human papillomavirus (HPV), human immunodeficiency virus (HIV), and pre-cancerous cervical lesions. Mycoplasmataceae infection in Tanzania is not well understood, especially when considering the differences between sexually transmitted species of Mycoplasmataceae. To establish the prevalence of common Mycoplasmataceae cervical infections and evaluate their relationship with risk factors for cervical cancer, 1160 Tanzanian women responded to an epidemiological questionnaire and were tested for HIV, HPV, cervical lesions, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma spp., and Lactobacillus iners. A subset of 134 women were used for 16s metagenomic sequencing of cervical DNA to establish the relative abundance of Mycoplasmataceae and Lactobacillus present. PCR detection of bacteria at the cervix found Ureaplasma spp. in 51.4% of women, M. hominis in 34%, M. genitalium in 2.3%, and L. iners in 75.6%. M. hominis and M. genitalium infection were significantly more prevalent among women with HPV and HIV. M. hominis prevalence was similar despite severity of cervical lesions; however, abundance of M. hominis increased significantly in women with cervical lesions. These results emphasize the importance of understanding the relationship between M. hominis and HPV-related cervical pathogenesis.

Relationship between the Cervical Microbiome, HIV Status, and Precancerous Lesions.

Nearly all cervical cancers are causally associated with human papillomavirus (HPV). The burden of HPV-associated dysplasias in sub-Saharan Africa is influenced by HIV. To investigate the role of the bacterial microbiome in cervical dysplasia, cytobrush samples were collected directly from cervical lesions of 144 Tanzanian women. The V4 hypervariable region of the 16S rRNA gene was amplified and deep sequenced. Alpha diversity metrics (Chao1, PD whole tree, and operational taxonomic unit [OTU] estimates) displayed significantly higher bacterial richness in HIV-positive patients (P = 0.01) than in HIV-negative patients. In HIV-positive patients, there was higher bacterial richness in patients with high-grade squamous intraepithelial lesions (HSIL) (P = 0.13) than those without lesions. The most abundant OTUs associated with high-grade squamous intraepithelial lesions were Mycoplasmatales, Pseudomonadales, and Staphylococcus We suggest that a chronic mycoplasma infection of the cervix may contribute to HPV-dependent dysplasia by sustained inflammatory signals.IMPORTANCE HPV is known to be the causal agent in the majority of cervical cancers. However, the role of the cervical bacterial microbiome in cervical cancer is not clear. To investigate that possibility, we collected cervical cytobrush samples from 144 Tanzanian women and performed deep sequencing of bacterial 16S rRNA genes. We found that HIV-positive patients had greater bacterial richness (P = 0.01) than HIV-negative patients. We also observed that women with high-grade squamous intraepithelial lesions (HSIL) had greater cervical bacterial diversity than women with cytologically normal cervices. Data from our precise sampling of cervical lesions leads us to propose that Mycoplasma contributes to a cervical microbiome status that promotes HPV-related cervical lesions. These results suggest a greater influence of the bacterial microbiota on the outcome of HPV infection than previously thought.

A Human Papillomavirus-Independent Cervical Cancer Animal Model Reveals Unconventional Mechanisms of Cervical Carcinogenesis.

HPV infections are common in healthy women and only rarely cause cervical cancer, suggesting that individual genetic susceptibility may play a critical role in the establishment of persistent HPV infection and the development of cervical cancer. Here, we provide convincing in vitro and in vivo evidence showing that differential expression and activation of YAP1 oncogene determine individual susceptibility to HPV infection and cervical carcinogenesis. We found that hyperactivation of YAP1 in mouse cervical epithelium was sufficient to induce invasive cervical cancer. Cervical epithelial cell-specific HPV16 E6/E7 and YAP1 double-knockin mouse model demonstrated that high-risk HPV synergized with hyperactivated YAP1 to promote the initiation and progression of cervical cancer. Our mechanistic studies indicated that hyperactivation of YAP1 in cervical epithelial cells facilitated HPV infection by increasing the putative HPV receptor molecules and disrupting host cell innate immunity. Our finding reveals an unconventional mechanism for cervical carcinogenesis.

Evolutionary and structural analyses of alpha-papillomavirus capsid proteins yields novel insights into L2 structure and interaction with L1.

BACKGROUND: PVs (PV) are small, non-enveloped, double-stranded DNA viruses that have been identified as the primary etiological agent for cervical cancer and their potential for malignant transformation in mucosal tissue has a large impact on public health. The PV family Papillomaviridae is organized into multiple genus based on sequential parsimony, host range, tissue tropism, and histology. We focused this analysis on the late gene products, major (L1) and minor (L2) capsid proteins from the family Papillomaviridae genus Alpha-papillomavirus. Alpha-PVs preferentially infect oral and anogenital mucosa of humans and primates with varied risk of oncogenic transformation. Development of evolutionary associations between PVs will likely provide novel information to assist in clarifying the currently elusive relationship between PV and its microenvironment (i.e., the single infected cell) and macro environment (i.e., the skin tissue). We attempt to identify the regions of the major capsid proteins as well as minor capsid proteins of alpha-papillomavirus that have been evolutionarily conserved, and define regions that are under constant selective pressure with respect to the entire family of viruses. RESULTS: This analysis shows the loops of L1 are in fact the most variable regions among the alpha-PVs. We also identify regions of L2, involved in interaction with L1, as evolutionarily conserved among the members of alpha- PVs. Finally, a predicted three-dimensional model was generated to further elucidate probable aspects of the L1 and L2 interaction.

Preparation and characterization of functionalized heparin-loaded poly-Ɛ-caprolactone fibrous mats to prevent infection with human papillomaviruses.

In this study, heparin-loaded poly-ɛ-caprolactone (PCL) fibrous mats were prepared and characterized based on their physical, cytotoxic, thermal, and biological properties. The main objective of the work described here was to test the hypothesis that incorporation of heparin into a PCL carrier could serve as bio-compatible material capable of inhibiting Human Papillomavirus (HPV) infection. The idea of firmly anchoring heparin to capture soluble virus, vs. a slow heparin release to inhibit a virus in solution was tested. Thus, one material was produced via conventional heparin matrix encapsulation and electrohydrodynamic fiber processing in one step. A second type of material was obtained via heparin crosslinking. This was achieved by running a carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling reaction on preformed PCL fibers. In vitro HPV16 L1 protein binding capacity studies were performed. Infectivity assays were done using HPV16 pseudoviruses (PsVs) carrying a GFP plasmid to directly test the ability of the fibrous mats to prevent internalization of HPV PsVs. The crosslinked heparin material presented a dissociation constant (Kd) value comparable to those found in the literature for different heparin-protein L1 peptide interactions. Both materials significantly reduced internalization of HPV PsVs, with a reduction of 94% of PsVs internalization when matrix encapsulated heparin-loaded material was present. Differences in performance between the two proposed structures are discussed.

The distribution of sexually-transmitted Human Papillomaviruses in HIV positive and negative patients in Zambia, Africa.

BACKGROUND: Human Papillomaviruses (HPV) are double-stranded DNA viruses, considered to be the primary etiological agents in cervical intraepithelial neoplasias and cancers. Approximately 15-20 of the 40 mucosal HPVs confer a high-risk of progression of lesions to invasive cancer. In this study, we investigated the prevalence of sexually transmitted HPVs in Human Immunodeficiency Virus (HIV) positive and negative patients in Zambia, Africa. The rate of high-risk HPV genotypes worldwide varies within each country. Thus, we sought to investigate the rates of HPV infection in sub-Saharan Africa and the potential role of HIV in affecting the HPV genotype distribution. METHODS: This retrospective cross-sectional study reports findings on the association and effects of HIV on HPV infections in an existing cohort of patients at University Teaching Hospital (UTH) Lusaka, Zambia. The objective of this study was to assess HPV prevalence, genotype distribution and to identify co-factors that influence HPV infection. Polymerase chain reaction (PCR) with two standard consensus primer sets (CpI/II and GP5+/6+) was used to test for the presence of HPV DNA. Primers specific for beta-actin were used to monitor DNA quality. Vaginal lavage samples, collected between 1998-1999 from a total of 70 women, were part of a larger cohort that was also analyzed for HIV and human herpesvirus infection. Seventy of the samples yielded usable DNA. HIV status was determined by two rapid assays, Capillus and Determine. The incidence of HIV and HPV infections and HPV genotype distributions were calculated and statistical significance was determined by Chi-Squared test. RESULTS: We determined that most common HPV genotypes detected among these Zambian patients were types 16 and 18 (21.6% each), which is approximately three-fold greater than the rates for HPV16, and ten-fold greater than the rates for HPV18 in the United States. The worldwide prevalence of HPV16 is approximately 14% and HPV18 is 5%. The overall ratio of high-risk (HR) to low-risk (LR) HPVs in the patient cohort was 69% and 31% respectively; essentially identical to that for the HR and LR distributions worldwide. However, we discovered that HIV positive patients were two-times as likely to have an HR HPV as HIV negative individuals, while the distribution of LR HPVs was unaffected by HIV status. Interestingly, we observed a nine-fold increase in HPV18 infection frequency in HIV positive versus HIV negative individuals. CONCLUSION: The rate of oncogenic HPVs (type 16 and 18) in Zambia was much higher than in the U.S., potentially providing an explanation for the high-rates of cervical cancer in Zambia. Surprisingly, we discovered a strong association between positive HIV status and the prevalence of HR HPVs, and specifically HPV18.

Seeing HPV in the New Light Offers a Glimpse of Heparin.

In this issue of Structure, Guan et al. (2017) describe cryo-EM mapping of human papillomavirus 16 (HPV16) capsids that propose locations for L2 and heparin binding sites. The high resolution of the modern cryo-EM methods (in this case down to 4.3 Å) opens great opportunities to probe conformational changes that take place during virus-receptor binding.

Differential localization of HPV16 E6 splice products with E6-associated protein.

High-risk Human Papillomavirus (HPV) is the etiological agent associated with the majority of anogenital cancers. The primary HPV oncogenes, E6 and E7, undergo a complex splicing program resulting in protein products whose purpose is not fully understood. Previous mouse studies have confirmed the existence of a translated product corresponding to the E6*I splice product. In terms of function, the translated E6*I protein has been shown to bind to E6 protein and to E6 associated protein (E6AP). E6*I has an inhibitory effect on E6-mediated p53 degradation in E6 expressing cells. In order to analyze the relationship between E6*I and full-length E6 in relation to localization, we created a series of green fluorescent protein (GFP) fusion products. The localization of these proteins with reference to E6AP in vivo remains unclear. Therefore, we investigated the cellular distribution of different forms of E6 with reference to E6AP. E6 and E6*I proteins, expressed from a wild type E6 gene cassette, were dispersed in the nucleus and the cytoplasm. Whereas, the E6 splice donor mutant (E6MT) was primarily localized to the nucleus. E6*I protein and E6AP were found to co-localize mainly to the cytoplasm, whereas the co-localization of full-length E6 protein and E6AP, if at all, was found mainly at the perinuclear region. These results suggest a functional relationship between the E6*I and full-length E6 protein which correlates with their localization and likely is important in regulation of the E6-E6AP complex.

Replication and encapsidation of papillomaviruses in Saccharomyces cerevisiae.

Improvements in methodologies to recapitulate and study particular biological functions of the papillomavirus life cycle have led to great advances in our knowledge of these viruses. Described in this chapter are techniques that allow low-copy and high-copy replication of full-length human papillomavirus (HPV) genomes, as well as assembly of virus-like particles, in Saccharomyces cerevisiae (yeast). This system has several distinct advantages that make it an attractive complement to the well-established raft-culturing system. First, yeast are inexpensive, rapid, and simple to culture in the lab. Second, they provide an ever-widening array of genetic tools to analyze HPV functions--most recently notable, the yeast open reading frame (ORF)-deletion library. Third, yeast provide a potentially high-efficiency means to produce large quantities of infectious virus in a short time frame. Fourth, assembly of HPV virus in yeast allows encapsidation of mutant genomes, since previous studies have shown that no viral ORF is required for replication of full-length HPV in yeast.