HPV-positive Cervical Cancers Research Articles

Population-level incidence of HPV-positive oropharyngeal, cervical, and anal cancers by smoking status.

We estimated the population-level incidence of human papillomavirus (HPV) positive oropharyngeal, cervical, and anal cancers by smoking status. We combined HPV DNA genotyping data from the Centers for Disease Control and Prevention's Cancer Registry Sentinel Surveillance System with data from the Kentucky Cancer Registry and Behavioral Risk Factor Surveillance System across smoking status. During 2004-2005 and 2014-2015 in Kentucky, most cases of oropharyngeal (63.3%), anal (59.7%), and cervical (54.9%) cancer cases were among persons who ever smoked. Population-level incidence rate was higher among persons who ever smoked than never smoked for HPV-positive oropharyngeal (7.8 vs 2.1; adjusted incidence rate ratio [RRadj] = 2.6), cervical (13.7 vs 6.8; RRadj = 2.0), and anal (3.9 vs 1.6; RRadj = 2.5) cancers. These findings indicate that smoking is associated with increased risk of HPV-positive oropharyngeal, cervical, and anal cancers, and the population-level burden of these cancers is higher among persons who ever smoked.

Reduced MHC Class I and II Expression in HPV-Negative vs. HPV-Positive Cervical Cancers.

Cervical cancer (CC) is the second most common cancer in women worldwide and the fourth leading cause of cancer-associated death in women. Although human papillomavirus (HPV) infection is associated with nearly all CC, it has recently become clear that HPV-negative (HPV-) CC represents a distinct disease phenotype with increased mortality. HPV-positive (HPV+) and HPV- CC demonstrate different molecular pathology, prognosis, and response to treatment. Furthermore, CC caused by HPV α9 types (HPV16-like) often have better outcomes than those caused by HPV α7 types (HPV18-like). This study systematically and comprehensively compared the expression of genes involved in major histocompatibility complex (MHC) class I and II presentation within CC caused by HPV α9 types, HPV α7 types, and HPV- CC. We observed increased expression of MHC class I and II classical and non-classical genes in HPV+ CC and overall higher expression of genes involved in their antigen loading and presentation apparatus as well as transcriptional regulation. Increased expression of MHC I-related genes differs from previous studies using cell culture models. These findings identify crucial differences between antigen presentation within the tumor immune microenvironments of HPV+ and HPV- CC, as well as modest differences between HPV α9 and α7 CC. These differences may contribute to the altered patient outcomes and responses to immunotherapy observed between these distinct cancers.

HPV-Positive and -Negative Cervical Cancers Are Immunologically Distinct.

Although infection with human papillomavirus (HPV) is associated with nearly all cervical cancers (CC), a small proportion are HPV-negative. Recently, it has become clear that HPV-negative CC represent a distinct disease phenotype compared to HPV-positive disease and exhibit increased mortality. In addition, variations between different HPV types associated with CC have been linked to altered molecular pathology and prognosis. We compared the immune microenvironments of CC caused by HPV α9 species (HPV16-like), HPV α7 species (HPV18-like) and HPV-negative disease. HPV-negative CC appeared distinct from other subtypes, with greatly reduced levels of lymphocyte infiltration compared to either HPV α9 or α7 CC. Besides reduced levels of markers indicative of B, T, and NK lymphocytes, the expression of T-cell effector molecules, activation/exhaustion markers, and T-cell receptor diversity were also significantly lower in HPV-negative CC. Interestingly, HPV-negative CC expressed much higher levels of potential neoantigens than HPV-positive CC. These results identify profound differences between the immune landscape of HPV-positive and HPV-negative CC as well as modest differences between HPV α9 and α7 CC. These differences may contribute to altered patient outcomes between HPV-negative and HPV-positive CC and potentially between CC associated with different HPV types.

Molecular Mechanisms of HIV Protease Inhibitors Against HPV-Associated Cervical Cancer: Restoration of TP53 Tumour Suppressor Activities.

Cervical cancer is a Human Papilloma virus-related disease, which is on the rise in a number of countries, globally. Two essential oncogenes, E6 and E7, drive cell transformation and cancer development. These two oncoproteins target two of the most important tumour suppressors, p53 and pRB, for degradation through the ubiquitin ligase pathway, thus, blocking apoptosis activation and deregulation of cell cycle. This pathway can be exploited for anticancer therapeutic interventions, and Human Immunodeficiency Virus Protease Inhibitors (HIV-PIs) have attracted a lot of attention for this anticancer drug development. HIV-PIs have proven effective in treating HPV-positive cervical cancers and shown to restore impaired or deregulated p53 in HPV-associated cervical cancers by inhibiting the 26S proteasome. This review will evaluate the role players, such as HPV oncoproteins involved cervical cancer development and how they are targeted in HIV protease inhibitors-induced p53 restoration in cervical cancer. This review also covers the therapeutic potential of HIV protease inhibitors and molecular mechanisms behind the HIV protease inhibitors-induced p53-dependent anticancer activities against cervical cancer.

Oral health problems are global and need to be addressed in the USA

Oral health problems are global and need to be addressed in the USA

Metabolic rewiring is associated with HPV-specific profiles in cervical cancer cell lines

Both HPV-positive and HPV-negative cervical cancers are associated with aberrant metabolism, although the oncogenic drivers remain elusive. Here we show the assessment of the metabolomic profiles of four distinct cervical cell lines, a normal and three cancer cell lines, one HPV-negative (C33A) and two HPV-positive (SiHa HPV16+, HeLa HPV18+), employing an ultra performance liquid chromatography and a high resolution mass spectrometry. Out of the total 462 metabolites, 248 to 326 exhibited statistically significant differences, while Random Forests analysis identified unique molecules for each cell line. The two HPV+ cell lines exhibited features of Warburg metabolism, consistent with the role of the HPV E6 protein. SiHa and HeLa cells displayed purine salvage pathway activity, while C33A cells revealed synthesis of cytidine, via a novel mechanism. These data document a highly dynamic HPV-specific rewiring of metabolic pathways occurring in cervical cancer. Therefore, this approach can eventually provide novel mechanistic insights into cervical carcinogenesis.

A Systems Approach Identifies Key Regulators of HPV-Positive Cervical Cancer

Cervical cancer has remained the most prevalent and lethal malignancy among women worldwide and accounted for over 250,000 deaths in 2019. Nearly ninety-five per cent of cervical cancer cases are associated with persistent infection with high-risk Human Papillomavirus (HPV), and seventy per cent of these are associated with viral integration in the host genome. HPV-infection imparts specific changes in the regulatory network of infected cancer cells that are of diagnostic, prognostic and importance. Here, we conducted a systems-level analysis of the regulatory network changes, and the associated regulatory proteins thereof, in HPV-positive cervical cancer. We applied functional pathway analysis to show that HPV-positive cancers are characterised by perturbations of numerous cellular processes, predominantly in those linked to the cell cycle, mitosis, cytokine and immune cell signalling. Using computational predictions, we revealed that HPV-positive cervical cancers are regulated by transcription factors including, SOX2, E2F, NANOG, OCT4, and MYC, which control various processes such as the renewal of cancer stem cells, and the proliferation and differentiation of tumour cells. Through the analysis of upstream regulatory kinases, we identified the mitogen-activated protein kinases; among others, MAPK1, MAPK3 and MAPK8, and the cyclin-dependent kinases; among others, CDK1, CDK2 and CDK4, as the key kinases that control the biological processes in HPV-positive cervical cancers. Taken together, we uncover a landscape of the key regulatory pathways and proteins in HPV-positive cervical cancers, all of which may provide attractive drug targets for future therapeutics.

An Exonuclease V–qPCR Assay to Analyze the State of the Human Papillomavirus 16 Genome in Cell Lines and Tissues

Integration of the human papillomavirus (HPV) genome into host cell chromosomes has been observed in a majority of HPV-positive cervical cancers and a subset of oral HPV-associated cancers. HPV integration also occurs in long-term cell culture. Screening for HPV integration can be labor intensive and yield results that are difficult to interpret. Here we describe an assay based on exonuclease V (ExoV/RecBCD) and quantitative polymerase chain reaction (qPCR) to determine if samples from cell lines and tissues contain episomal or integrated HPV. This assay can be applied to screen other small DNA viruses with episomal/linear genome configurations in their viral lifecycle and has the potential to be used in clinical settings to define viral genomic conformations associated with disease. © 2020 Wiley Periodicals LLC. Basic Protocol: Exonuclease V genomic DNA digestion and qPCR for detection of HPV16 genome configuration in cells Support Protocol: Exonuclease V analysis of HPV16 genome configuration in tissues Alternate Protocol: Determining HPV integration type or integrity of HPV episome.

HPV E2, E4, E5 drive alternative carcinogenic pathways in HPV positive cancers

The dominant paradigm for HPV carcinogenesis includes integration into the host genome followed by expression of E6 and E7 (E6/E7). We explored an alternative carcinogenic pathway characterized by episomal E2, E4, and E5 (E2/E4/E5) expression. Half of HPV positive cervical and pharyngeal cancers comprised a subtype with increase in expression of E2/E4/E5, as well as association with lack of integration into the host genome. Models of the E2/E4/E5 carcinogenesis show p53 dependent enhanced proliferation in vitro, as well as increased susceptibility to induction of cancer in vivo. Whole genomic expression analysis of the E2/E4/E5 pharyngeal cancer subtype is defined by activation of the fibroblast growth factor receptor (FGFR) pathway and this subtype is susceptible to combination FGFR and mTOR inhibition, with implications for targeted therapy.

EGFR Activation is Suppressed by High Doses of Folic Acid in HPV Negative Cervical Cancer Cells

Cervical cancer is one of the leading causes of death due to cancer in women. Human Papilloma Virus infection is the primary risk factor for developing cervical cancer, however very little is known about HPV negative cervical cancers. Folate fortification of flour for prevention of neural tube defects has been mandatory in North America since 1998; and folate supplementation is recommended during pregnancy. Folate fortification is not mandated in all countries, however, due to concerns about possible adverse effects on cancer incidence or prognosis. There is evidence that folate intake can reduce risk of developing tumors but other contradictory studies indicate that supraphysiologic doses of folate can actually lead to disease progression. Folate receptor alpha is known to be expressed in many cancer cell lines, including HPV positive cervical cancer. There is some evidence that folic acid can promote methylation of the EGFR, leading to a decrease in EGFR expression, and that EGFR might be active in some HPV positive cervical cancers. The purpose of this study is to determine if EGFR plays a role in HPV negative cervical cancer cell growth, and the effects of folic acid on EGFR protein expression and activation. Two HPV negative cervical cancer cell lines were used for this study: C33A and DoTc2‐4510. High doses of folic acid caused a decrease in both C33A and DoTc cell proliferation. Interestingly, qPCR and western blotting analysis indicate that only the DoTc2‐4510 cells expressed EGFR. The DoTc2‐4510 cells were sensitive to the EGFR inhibitor, gefinitib, with an IC50 of 0.01 uM. There was no change in EGFR expression upon folic acid treatment, but interestingly high doses of folic acid did inhibit EGFR activation. Taken together this data indicates that EGFR may be a target for a subset of HPV negative cervical cancers, and that high doses of folic acid may help prevent EGFR positive HPV negative cervical cancer cell growth.

Prognostic implications of genotyping and p16 immunostaining in HPV-positive tumors of the uterine cervix.

Human papillomaviruses (HPVs) are the causative agents of carcinoma of the uterine cervix. A number of HPV genotypes have been associated with cervical cancer and almost all tumors associated with HPV show strong p16 expression. However, there is little information on the possible impact of the HPV genotype and p16 immunostaining on the clinicopathological features or their prognostic value in cervical carcinoma. We evaluated a series of 194 patients with HPV-positive cervical cancers treated at our institution, focusing on the clinicopathological features and the relationship of the HPV genotypes and p16 immunostaining with the prognosis. A single HPV type was identified in 149 (77%) tumors, multiple HPV infection was detected in 30 cases (15%), and undetermined HPV type/s were identified in 15 (8%) carcinomas. HPV 16 and/or 18 were detected in 156 (80%) tumors. p16 was positive in 186 (96%) carcinomas, but eight tumors (4%) were negative for p16 (seven squamous cell carcinomas, one adenocarcinoma); 5/8 caused by HPV 16 and/or 18. Patients with HPV 16 and/or 18 were younger (49 ± 15 vs. 57 ± 17 years, p < 0.01) and more frequently had nonsquamous tumors than patients with other HPV types (24% [37/156] vs. 0% [0/38]; p = 0.01). Neither the HPV type nor multiple infection showed any prognostic impact. Patients with p16-negative tumors showed a significantly worse overall survival than women with p16-positive carcinomas (45 vs. 156 months, p = 0.03), although no significant differences in disease-free survival were observed. In the multivariate analysis, negative p16 immunostaining was associated with a worse overall survival together with advanced FIGO stage and lymph node metastases. In conclusion, the HPV genotype has limited clinical utility and does not seem to have prognostic value in cervical cancer. In contrast, a negative p16 result in patients with HPV-positive tumors is a prognostic marker associated with a poor overall survival.

Feasibility of miR-9, miR-21, and miR-155 as alternative biomarkers in both HPV-positive and HPV-negative cervical cancers.

52 Background: Cervical cancer is the second leading cause of death among female patients with cancer in the world. High risk human papillomavirus has causal roles in cervical cancer initiation and progression by deregulating several cellular processes. However, HPV infection is not sufficient for cervical carcinoma development. Therefore, other genetic and epigenetic factors may be involved in this complex disease, and the identification of which may lead to better diagnosis and treatment. Our aim was to analyze the expression of microRNAs in cervical cancer cases positive or negative for HPV E6/E7 mRNA, and to assess their diagnostic usefulness and relevance. Methods: The expression of three different microRNAs (miR-9, miR-21, and miR-155) in 52 formalin-fixed paraffin-embedded (FFPE) primary cervical cancer tissue samples and 50 FFPE normal cervical tissue samples were evaluated. Results: MiR-9, miR-21, and miR-155 were significantly overexpressed in cervical cancer tissues compared to normal tissues ( P &lt; 0.001). MiR-9, miR-21, and miR-155 expression combined with the HPV E6/E7 mRNA assay showed sensitivities of 82.7 %, 92.3 %, and 84.6 % respectively, demonstrating their potential as diagnostic tools. Moreover, miR-21 and miR-155 were predictors showing a 7 fold and 10.3 fold higher risk for HPV E6/E7 negative patients with cervical cancer ( P = 0.024 and P = 0.017, respectively) while miR-155 was a predictor showing a 27.9 fold higher risk for HPV E6/E7 positive patients with cervical cancer ( P &lt; 0.0001). Conclusions: There is a strong demand for additional, alternative molecular biomarkers for diagnosis and management of precancer patients. MiR-9, miR-21, and miR-155 may be helpful in the prediction of both HPV positive and HPV negative cases of cervical cancer.

Beta emitters rhenium-188 and lutetium-177 are equally effective in radioimmunotherapy of HPV-positive experimental cervical cancer.

Cervical cancer caused by the infection with the human papillomavirus (HPV) remains the fourth leading killer of women worldwide. Therefore, more efficacious treatments are needed. We are developing radioimmunotherapy (RIT) of HPV-positive cervical cancers by targeting E6 and E7 viral oncoproteins expressed by the cancer cells with the radiolabeled monoclonal antibodies (mAbs). To investigate the influence of different radionuclides on the RIT efficacy-we performed RIT of experimental cervical cancer with Rhenium-188 ((188) Re) and Lutetium-177 ((177) Lu)-labeled mAb C1P5 to E6. The biodistribution of (188) Re- and (177) Lu-labeled C1P5 was performed in nude female mice bearing CasKi cervical cancer xenografts and the radiation dosimetry calculations for the tumors and organs were carried out. For RIT the mice were treated with 7.4 MBq of either (188) Re-C1P5 or (177) Lu-C1P5 or left untreated, and observed for their tumor size for 28 days. The levels of (188) Re- and (177) Lu-C1P5 mAbs-induced double-strand breaks in CasKi tumors were compared on days 5 and 10 post treatment by staining with anti-gamma H2AX antibody. The radiation doses to the heart and lungs were similar for both (177) Lu-C1P5 and (188) Re-C1P5. The dose to the liver was five times higher for (177) Lu-C1P5. The doses to the tumor were 259 and 181 cGy for (177) Lu-C1P5 and (188) Re-C1P5, respectively. RIT with either (177) Lu-C1P5 or (188) Re-C1P5 was equally effective in inhibiting tumor growth when each was compared to the untreated controls (P = 0.001). On day 5 there was a pronounced staining for gamma H2AX foci in (177) Lu-C1P5 group only and on day 10 it was observed in both (177) Lu-C1P5 and (188) Re-C1P5 groups. (188) Re- and (177) Lu-labeled mAbs were equally effective in arresting the growth of CasKi cervical tumors. Thus, both of these radionuclides are candidates for the clinical trials of this approach in patients with advanced, recurrent or metastatic cervical cancer.

Hypermethylation of the tumor-suppressor cell adhesion molecule 1 in human papillomavirus-transformed cervical carcinoma cells.

Epigenetic modification at CpG islands located on the promoter regions of tumor-suppressor genes has been associated with tumor development in many human cancers. Our study showed that the cell adhesion molecule 1 (CADM1) is downregulated in human papillomavirus (HPV)-infected cervical cancer cell lines via its hypermethylation and demethylation using 5-aza-2′-deoxycyticine (5-aza-dC) restored the expression of CADM1 protein. Overexpression of CADM1 inhibited cell proliferation. p53 was involved in the regulation of CADM1. Our results demonstrate that epigenetic alteration of CADM1 was more frequent in HPV-positive cervical cancers and that restoration of CADM1 expression may be a potential strategy for cervical cancer therapy.

Type-specific HPV prevalence in invasive cervical cancer in the UK prior to national HPV immunisation programme: baseline for monitoring the effects of immunisation

AimsTo establish the human papillomavirus (HPV) type-specific prevalence in cervical cancer and high-grade cervical lesions in the UK prior to the introduction of national HPV vaccination.MethodsSpecimens of cervical cancer (n=1235)...

Are 20 human papillomavirus types causing cervical cancer?

In 2012, the International Agency for Research on Cancer concluded that there was consistent and sufficient epidemiological, experimental and mechanistic evidence of carcinogenicity to humans for 12 HPV types (HPV16, HPV18, HPV31, HPV33, HPV35, HPV39, HPV45, HPV51, HPV52, HPV56, HPV58 and HPV59) for cervical cancer. Therefore, these types were considered as 1A carcinogens. They all belong to the family of the α-Papillomaviridae, in particular to the species α5 (HPV51), α6 (HPV56), α7 (HPV18, HPV39, HPV45, HPV59) and α9 (HPV16, HPV31, HPV33, HPV35, HPV52, HPV58). Less evidence is available for a thirteenth type (HPV68, α7), which is classified as a 2A carcinogen (probably carcinogenic). Moreover, seven other phylogenetically related types (HPV26, HPV53, HPV66, HPV67, HPV68, HPV70 and HPV73) were identified as single HPV infections in certain rare cases of cervical cancer and were considered possibly carcinogenic (2B carcinogens). Recently, Halec et al [7] demonstrated that the molecular signature of HPV-induced carcinogenesis (presence of type-specific spliced E6*| mRNA; increased expression of p16; and decreased expression of cyclin D1, p53 and Rb) was similar in cervical cancers containing single infections with one of the eight afore-mentioned 2A or 2B carcinogens to those in cancers with single infections with group 1 carcinogens. Ninety six percent of cervical cancers are attributable to one of the 13 most common HPV types (groups 1 and 2A). Including the additional seven HPV types (group 2B) added 2.6%, to reach a total of 98.7% of all HPV-positive cervical cancers. From recently updated meta-analyses, it was shown that HPV68, HPV26, HPV66, HPV67, HPV73 and HPV82 were significantly more common in cancer cases than in women with normal cervical cytology, suggesting that for these HPV types, an upgrading of the carcinogen classification could be considered. However, there is no need to include them in HPV screening tests or vaccines, given their rarity in cervical cancers.

Abstract PR08: Identification of novel methylated genomic regions in invasive cervical cancer using a genome-wide approach

Abstract Introduction: In the US, an estimated 35,000 cancer cases per year are attributable to Human papillomavirus (HPV), including cancers of the cervix, anus and oropharynx. Despite the availability of an HPV-targeted vaccine, issues with low uptake and significant lag time from vaccination to cancer prevention will result in cervical cancer continuing to be a substantial burden to US and world-wide populations. It is becoming increasingly clear that epigenetic events play a critical role in HPV-associated carcinogenesis, including changes in host genome DNA methylation patterns. In the cervix, methylation patterns have been shown to be altered; however, there have been inconclusive findings as to the most informative methylation targets in cervical cancer. We hypothesize that there are novel epigenetic alterations in HPV-associated cervical cancer and these changes may be early detection biomarkers in pre-invasive cervical lesions. In this study, we sought to identify epigenetic differences in HPV-positive cervical cancers compared to HPV-positive normal tissue using genome-wide methylation arrays and to explore if these differences can be identified in cervical intraepithelial neoplasia (CIN) 3 lesions. Methods: DNA was extracted from 24 frozen cervical tissues (9 normal, 5 CIN 3 and 10 invasive cancers) following pathology review and macrodissection. Bisulfite-modified DNA was interrogated for methylation at over 450,000 CpG loci using the Illumina HumanMethylation450 BeadChip array. HPV genotyping was conducted using SFP10 LiPA HPV-typing system. Differential methylation between normal and tumors at individual CpG loci was determined by t-test with significance set by a false discovery rate (or q-value) and final sets were restricted to those with a mean difference in β-values≥0.3. Next, using a window-based approach, we examined clusters of CpG loci within gene coding regions or CpG islands. Finally, a binary classification strategy was used for each gene set of probes, where a probe was defined as methylated if the β-values were above the minimum point in the bi-modal histogram. Sensitivity and specificity for each gene at the set methylation cut-point was determined. Results: A total of 24 HPV positive tissues were examined in this study (9 normal, 5 CIN 3 and 10 invasive cancers). A total of 321 CpG loci displayed differential methylation with mean difference ≥0.5 in tumors compared to normal (FDR corrected q&amp;lt;0.0005), of which 310 were hypermethylated and 11 were hypomethylated in tumors. We examined CpG site clusters within gene-coding regions among a larger set of 13,515 loci differentially methylated using less stringent criteria (q&amp;lt;0.01, β-value difference≥0.3). A total of 369 genes demonstrated differential methylation across clusters of CpG loci (12-1293 CpG sites per gene) between normal and tumors. Of these 369 genes, 80 were differentially methylated in ≥50% of CpG loci evaluated within the gene. Methylation status of 19 genes had both a sensitivity and specificity for distinguishing tumor from normal of 100%, including MIR129-2, protocadherin 10 (PCDH-10), and POU class 3 homeobox 3 (POU3F3). All 19 genes were also differentially methylated in at least one CIN 3 lesion. Conclusions: We have identified several novel methylated CpG loci and genomic regions in HPV-associated cervical cancer, some of which were also found to be altered in CIN 3 lesions. Validation of these novel CpG loci in a larger population of women with cervical dysplasia and cancer is warranted. A number of these novel methylated sites may emerge as promising biomarkers for the early detection of cervical cancer and possibly, for other HPV-associated malignancies. This abstract is also presented as Poster C24. Citation Format: Erin M. Siegel, Anders Berglund, Bridget Riggs, Steven Eschrich, Maddox Kristen, Abidemi Ajidahun, David Shibata, Kevin D. Brown. Identification of novel methylated genomic regions in invasive cervical cancer using a genome-wide approach. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr PR08.

Chloroform Extract of Rasagenthi Mezhugu, a Siddha Formulation, as an Evidence-Based Complementary and Alternative Medicine for HPV-Positive Cervical Cancers.

Rasagenthi Mezhugu (RGM) is a herbomineral formulation in the Siddha system of traditional medicine and is prescribed in the southern parts of India as a remedy for all kinds of cancers. However, scientific evidence for its therapeutic efficacy in cervical cancer is lacking, and it contains heavy metals. To overcome these limitations, RGM was extracted, and the fractions were tested on HPV-positive cervical cancer cells, ME-180 and SiHa. The extracts, free from the toxic heavy metals, affected the viability of both the cells. The chloroform fraction (cRGM) induced DNA damage and apoptosis. Mitochondria-mediated apoptosis was indicated. Though both the cells responded to the treatment, ME-180 was more responsive. Thus, this study brings up scientific evidence for the efficacy of RGM against the HPV-mediated cervical cancer cells and, if the toxic heavy metals are the limitation in its use, cRGM would be a suitable candidate as evidence-based complementary and alternative medicine for HPV-positive cervical cancers.

RNA Interference of Human Papillomavirus Type 16 E7 Increases HLA Class I Antigen Expression in HaCaT-E7 Cells

High-risk human papillomaviruses (HPVs) are the major causative agents of cervical cancer. The E7 protein of high-risk HPV disturbs cell cycle control and down-regulates components of the antigen presentation pathway, suggesting an ideal target for development of the immunotherapy in HPV-positive cervical cancers. We previously reported that HPV16 E7 could down-regulate cell-surface HLA class I antigen accompanying decreased expression of transporter associated with antigen processing 1 (TAP-1). The purpose of this study was to determine whether knockdown of HPV16 E7 could up-regulate surface HLA class I antigen expression in HPV16 E7 expressing HaCaT cells (HaCaT-E7). An E7-specific small interfering RNA (siRNA) was transfected into the HaCaT-E7 cells, and the expression of HPV16 E7 was measured by real-time reverse transcriptase polymerase chain reaction and Western blot. With the use of flow cytometry analysis, the levels of cell surface HLA class I antigen and intracellular TAP-1 expression were detected. It was found that transfection of HPV16 E7-siRNA reduced HPV16 E7 expression as measured on messenger RNA and protein levels. The flow cytometry analysis showed that, compared with mock transfection, a statistically significant increase of approximately 75% in surface HLA class I levels was observed in HaCaT-E7 cells at 72 hours after transfection of E7 siRNA. Moreover, he knockdown of E7 in HaCaT-E7 cells could result in an increase of intracellular TAP-1 expression, which is essential for the expression of HLA class I at cell surface. Our study showed that the knockdown of HPV16 E7 could increase cell surface HLA class I antigen expression in HaCaT-E7 cells. In addition, for HPV-positive human cervical cancer, our observations indicate that the HPV E7 gene is a target of choice.

Effect of simultaneous silencing of HPV-18 E6 and E7 on inducing apoptosis in HeLa cellsThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process.

The objective of this investigation was to determine if simultaneous silencing of the human papillomavirus type 18 (HPV-18) E6 and E7 oncogenes using RNA interference (RNAi) would be a potential therapeutic approach against the carcinogenic activity of this virus. Two synthetic double-stranded oligonucleotides, encoding short hairpin transcripts corresponding to HPV-18 E6 and E7 genes, were cloned into pGenesilence (pGS) 1.0 vectors to produce pGS-E6, pGS-E7, and pGS-(E6+E7), respectively. Our results showed that the expression of HPV-18 E6 class 1 and HPV-18 E7 in HeLa cells was markedly decreased after being transfected with pGS-E6, pGS-E7, and pGS-(E6+E7) vectors. Of the three vectors, pGS-(E6+E7) had a greater ability to decrease the growth rate of HeLa cells, inhibit colony formation in soft agar, and significantly reduce tumor growth in nude mice. We also found that depletion of HPV-18 E6 and E7 in this manner promoted apoptosis of HeLa cells. Our data showed that simultaneously decreasing HPV-18 E6 and E7 gene expression in HeLa cells by RNAi could significantly inhibit tumor growth under in vitro conditions and in nude mice. These data suggest that gene therapy may be a possible therapeutic approach for HPV-positive cervical cancers.