mTOR Pathway Activation Assessed by Immunohistochemistry in Cervical Biopsies of HPV-associated Endocervical Adenocarcinomas (HPVA): Correlation With Silva Invasion Patterns

The Silva pattern of invasion, recently introduced to stratify patients at risk for lymph node metastases in human papillomavirus-associated endocervical adenocarcinomas (HPVAs), can only be assessed in cone and loop electrosurgical excision procedure excisions with negative margins or in a hysterectomy specimen. Previous studies found associations between destructive stromal invasion patterns (Silva patterns B and C) and mutations in genes involved in the MEK/PI3K pathways that activate the mammalian target of rapamycin (mTOR) pathway. The primary aim of this study was to use cervical biopsies to determine whether markers of mTOR pathway activation associate with aggressive invasion patterns in matched excision specimens. The status of the markers in small biopsy specimens should allow us to predict the final and biologically relevant pattern of invasion in a resection specimen. Being able to predict the final pattern of invasion is important, since prediction as Silva A, for example, might encourage conservative clinical management. If the pattern in the resection specimen is B with lymphovascular invasion or C, further surgery can be performed 34 HPVA biopsies were evaluated for expression of pS6, pERK, and HIF1α. Immunohistochemical stains were scored semiquantitatively, ranging from 0 to 4+ with scores 2 to 4+ considered positive, and Silva pattern was determined in follow-up excisional specimens. Silva patterns recognized in excisional specimens were distributed as follows: pattern A (n=8), pattern B (n=4), and pattern C (n=22). Statistically significant associations were found comparing pS6 and pERK immunohistochemistry with Silva pattern (P=0.034 and 0.05, respectively). Of the 3 markers tested, pERK was the most powerful for distinguishing between pattern A and patterns B and C (P=0.026; odds ratio: 6.75, 95% confidence interval: 1.111-41.001). Although the negative predictive values were disappointing, the positive predictive values were encouraging: 90% for pERK, 88% for pS6 and 100% for HIF1α. mTOR pathway activation assessed by immunohistochemistry in cervical biopsies of HPVA correlate with Silva invasion patterns.

Glutathione Peroxidase (GPx) and Superoxide Dismutase (SOD) in Oropharyngeal Cancer Associated with EBV and HPV Coinfection

Recent reports have pointed to the link between persistent inflammation, oxidative stress, and carcinogenesis; however most of the studies concerning the role of viruses in head and neck cancer (HNC) are focused mainly on one type of virus. Our present study aimed to study the relationship between Epstein-Barr virus/human papilloma virus (EBV/HPV) coinfection and glutathione peroxidase (GPx) and superoxide dismutase (SOD) level in oropharyngeal cancer. Fresh-frozen tumor tissue samples were collected from 128 patients with oropharyngeal cancer infected with EBV or HPV or with EBV/HPV coinfection. After DNA extraction, EBV and HPV DNA was detected using a polymerase chain reaction (PCR) assay. GPx and SOD activity was determined in homogenates of cancer tissue using diagnostic kits produced by Randox Laboratories. Both GPx and SOD activity was statistically lower in patients with EBV/HPV coinfection than in a single EBV or HPV infection. Analysis of GPx and SOD activity in relation to histological grading and tumor, node (TN) classification revealed that in poorly-differentiated tumors, the level of antioxidant enzymes was lower compared with well-differentiated lesions and in cases with greater tumor dimensions and lymph-node involvement, both GPx and SOD activity was decreased. Further studies are necessary to clarify the influence of interplay between EBV, HPV, and oxidative stress on malignant transformation of upper aerodigestive tract epithelial cells.

Polymorphism of MMP1 and MMP3 promoter regions and HR-HPV infection in women from Burkina Faso and Côte d'Ivoire

The single nucleotide polymorphism (SNP) of the promoter region of MMP-1 (at 1607 bp) and MMP-3 (at 1171 bp) create Ets binding sites. Correlations between these SNPs and sensitivity to several biological processes such as metastasis and recurrence of cancer have been reported in several studies. In this case-control study, we looked for these SNPs in women infected with or not with high-risk human papillomaviruses (HR-HPV). The frequency, distribution and correlation of these SNPs with the presence or absence of HR-HPV infection were evaluated. Genotypes 1G1G, 1G2G and 2G2G for MMP1 and genotypes 5A5A, 5A6A, 6A6A for MMP3 were found in our study population. In general, we noted that the 1G (40.8%) and 2G (64.8%) alleles were more frequent in non-infected women and infected women, respectively, and more specifically this difference was significant in women from Côte d'Ivoire. These results, although yet to be reaffirmed with assays for quantifying the mRNA of these genes, suggest that the SNP of the MMP-1 promoter could promote infection with HR-HPV.

Mutations in the HPV16 genome induced by APOBEC3 are associated with viral clearance

HPV16 causes half of cervical cancers worldwide; for unknown reasons, most infections resolve within two years. Here, we analyze the viral genomes of 5,328 HPV16-positive case-control samples to investigate mutational signatures and the role of human APOBEC3-induced mutations in viral clearance and cervical carcinogenesis. We identify four de novo mutational signatures, one of which matches the COSMIC APOBEC-associated signature 2. The viral genomes of the precancer/cancer cases are less likely to contain within-host somatic HPV16 APOBEC3-induced mutations (Fisher's exact test, P = 6.2 x 10-14), and have a 30% lower nonsynonymous APOBEC3 mutation burden compared to controls. We replicate the low prevalence of HPV16 APOBEC3-induced mutations in 1,749 additional cases. APOBEC3 mutations also historically contribute to the evolution of HPV16 lineages. We demonstrate that cervical infections with a greater burden of somatic HPV16 APOBEC3-induced mutations are more likely to be benign or subsequently clear, suggesting they may reduce persistence, and thus progression, within the host.

Multiple regions of E6AP (UBE3A) contribute to interaction with papillomavirus E6 proteins and the activation of ubiquitin ligase activity

The HECT domain E3 ubiquitin ligase E6AP (UBE3A) is critical for the development of human papillomavirus (HPV) associated cancers, the neurodevelopment disorder Angelman Syndrome, and some cases of autism spectrum disorders. How E6AP recognizes its cellular targets and how its ubiquitin ligase activity is triggered remain poorly understood, and HPV E6 proteins are models for these processes. We examined diverse E6 proteins from human and non-human papillomaviruses and identified two different modes of interaction between E6 and E6AP. In Type I interactions, E6 can interact directly with the LXXLL peptide motif alone of E6AP (isolated from the rest of E6AP), and then recruit cellular substrates such as p53. In Type II interactions, E6 proteins require additional auxiliary regions of E6AP in either the amino terminus or in the carboxy-terminal HECT domain to interact with the LXXLL peptide motif of E6AP. A region of E6AP amino-terminal to the LXXLL peptide motif both augments association with E6 proteins and is required for E6 proteins to trigger ubiquitin ligase activity in the carboxy-terminal HECT ubiquitin ligase domain of E6AP. In Type I interactions, E6 can associate with E6AP and recruit p53, but a Type II interaction is required for the degradation of p53 or NHERF1. Interestingly, different E6 proteins varied in E6AP auxiliary regions that contributed to enhanced association, indicating evolutionary drift in the formation of Type II interactions. This classification of E6-E6AP interaction types and identification of a region in the E6AP amino terminus that is important for both E6 association and stimulation of ubiquitin ligase activity will inform future structural data of the E6-E6AP complex and future studies aiming to interfere with the activity of the E6-E6AP complex.

Genomic alterations in STK11 can predict clinical outcomes in cervical cancer patients

OBJECTIVE

Cervical cancer is the fourth most common cause of cancer-related deaths in Asian women, due to its poor prognosis. This study aimed to decipher genomic alteration profiles of a cohort of Japanese cervical cancer patients to understand why certain patients benefited from molecular targeted therapies and their prognostic significance.

METHODS

During 2008-2018, 154 cervical cancer patients underwent a potentially curative resection procedure at the National Cancer Center Hospital. Genomic DNA samples were analyzed using Ion AmpliSeq™ Cancer Hotspot Panel v2. Alterations in the copy number of PIK3CA, ERBB2, PTEN, and STK11 were detected using the TaqMan assay. HPV-positive results were confirmed by genomic testing and in situ hybridization assay.

RESULTS

The frequency of genomic alterations in PIK3CA (36%), STK11 (16%), PTEN (11%), TP53 (11%), and KRAS (8%) was >5%. KRAS mutations were preferentially detected in patients with adenocarcinomas, and the frequency of PIK3CA mutations in patients with squamous cell carcinomas was higher than that in patients with other histological cancer types. HPV-positive results were observed in 139/154 (90.3%) patients, and TP53 mutants were detected in HPV-negative specimens. In this study, the overall survival of patients with genomic alterations in STK11 was worse than in patients with wild-type STK11 (hazard ratio = 10.6, P = 0.0079) and TCGA dataset (hazard ratio = 2.46, P = 0.029).

CONCLUSIONS

More than one-third of Japanese cervical cancer patients exhibit mutations targeted by molecular targeted therapies. We have proposed the prognostic value of STK11 genomic alterations.

Association of the MUTYH Gln324His (CAG/CAC) variant with cervical carcinoma and HR-HPV infection in a Chinese population

This study was performed to investigate the relationship between the MUTYH Gln324His (CAG/CAC) genotype and risk of cervical squamous cell carcinoma (CSCC) in a case-control setting. Mismatch amplification-polymerase chain reaction (MA-PCR) was applied to detect the polymorphism in 400 CSCC, 400 CIN III and 1200 control participants. The homozygous His324His (CAC/CAC) genotype of MUTYH was associated with significantly increased risk of CIN III (OR = 1.94) and CSCC (OR = 3.83). Increased risk of CIN III (OR = 1.34) and CSCC (OR = 1.97) was additionally observed with the heterozygous CAG/CAC genotype. Overall, individuals in both CAC/CAC and CAG/CAC genotype groups were at higher risk of cervical carcinoma (CINIII (OR = 1.46) and CSCC (OR = 2.34)). Within the HR-HPV infection-positive group, CAC/CAC and CAG/CAC genotypes were significantly enriched in relation to CIN III and CSCC. Moreover, we observed a positive correlation between the proportion of homozygous CAC/CAC MUTYH genotype and malignant prognostic factors of CSCC, such as cell differentiation grade and lymph node metastasis. These findings clearly highlight associations between the MUTYH Gln324His (CAG/CAC) polymorphism and susceptibility to CSCC, HR-HPV infection and specific prognostic factors, supporting the utility of this variant as an early indicator for patients at high risk of cervical carcinoma.

USP15 inhibits HPV16 E6 degradation and catalytically inactive USP15 has reduced inhibitory activity

High-risk human papillomaviruses (HPVs) possess transforming activity leading to development of the cancer, including oropharyngeal, anal, penile, vulvar, vaginal, and cervical cancer. The stability of E6 is essential for its complete function as an oncoprotein. Using the yeast two-hybrid system, we identified ubiquitin-specific protease 15 (USP15) as an HPV16 E6-interacting protein. USP15 cleaves polyubiquitin chains of HPV16 E6 and/or ubiquitin precursors. Our results indicate that USP15 could increase the level of HPV16 E6 by inhibiting E6 degradation. USP15 inhibited the degradation of HPV16 E6 in dose-dependent manner. In contrast, catalytically inactive mutants of USP15 had a reduced inhibitory effect on E6 degradation. In particular, USP15 mutants of all three cysteine boxes and the NHL mutant of the KRF box had a drastically reduced inhibitory effect on HPV16 E6 degradation. In addition, HPV16 E6 mRNA was not induced by USP15; therefore, HPV16 E6 appears to be post-translationally regulated. These results suggest that USP15 has the ability to stabilize E6 as a deubiquitinating enzyme, and as an oncoprotein affects biological functions in infected human cells.

HPV31 utilizes the ATR-Chk1 pathway to maintain elevated RRM2 levels and a replication-competent environment in differentiating Keratinocytes

Productive replication of human papillomaviruses (HPV) is restricted to the uppermost layers of the differentiating epithelia. How HPV ensures an adequate supply of cellular substrates for viral DNA synthesis in a differentiating environment is unclear. Here, we demonstrate that HPV31 positive cells exhibit increased dNTP pools and levels of RRM2, a component of the ribonucleotide reductase (RNR) complex, which is required for de novo synthesis of dNTPs. RRM2 depletion blocks productive replication, suggesting RRM2 provides dNTPs for viral DNA synthesis in differentiating cells. We demonstrate that HPV31 regulates RRM2 levels through expression of E7 and activation of the ATR-Chk1-E2F1 DNA damage response, which is essential to combat replication stress upon entry into S-phase, as well as for productive replication. Our findings suggest a novel way in which viral DNA synthesis is regulated through activation of ATR and Chk1 and highlight an intriguing new virus/host interaction utilized for viral replication.

Expression of Cyclooxygenase-2 in naturally occurring bovine cutaneous fibropapillomas

Bovine cutaneous fibropapillomas are benign skin tumours characterized by epithelial and dermal proliferation and induced by Bovine papillomaviruses (BPVs). Cyclooxygenase (COX) 1 and 2 are enzymes involved in pathological conditions, such as inflammation and epithelial carcinogenesis. Here we investigated biochemically and immunohistochemically COX-2 expression in bovine cutaneous fibropapillomas. Eight of twelve fibropapillomas (67%) showed COX-2 positive immunosignal mostly in the cytoplasm of the basal cell layer, while the normal skin did not stain. Biochemical analysis confirmed the expression of COX-2 in tumour samples. This study shows COX-2 expression in cutaneous fibropapillomas, suggesting a contribution in epithelial tumour development.

Phosphorylation of bovine papillomavirus E1 by the protein kinase CK2 near the nuclear localization signal does not influence subcellular distribution of the protein in dividing cells

The bovine papillomavirus E1 helicase is essential for viral replication. In dividing cells, DNA replication maintains, but does not increase, the viral genome copy number. Replication is limited by low E1 expression and an E1 nucleocytoplasmic shuttling mechanism. Shuttling is controlled in part by phosphorylation of E1 by cellular kinases. Here we investigate conserved sites for phosphorylation by kinase CK2 within the E1 nuclear localization signal. When these CK2 sites are mutated to either alanine or aspartic acid, no change in replication phenotype is observed, and there is no effect on the subcellular distribution of E1, which remains primarily nuclear. This demonstrates that phosphorylation of E1 by CK2 at these sites is not a factor in regulating viral DNA replication in dividing cells.

Methylation of human papillomavirus 16, 18, 31, and 45 L2 and L1 genes and the cellular DAPK gene: Considerations for use as biomarkers of the progression of cervical neoplasia

During progression of cervical cancer, human papillomavirus genomes and cellular tumor suppressor genes can become methylated. Toward a better understanding of these biomarkers, we studied 104 samples with HPV16, 18, 31, and 45 representing five pathological categories from asymptomatic infection to cancer. We grouped all samples by HPV type and pathology and measured the overall methylation of informative amplicons of HPV late genes and the cellular DAPK gene. Methylation of all four HPV types as well as of the DAPK gene is lowest in asymptomatic infection and increases successively in all four pathological categories during progression to cancer. 27 out of 28 cancer samples showed methylation both in the L2/L1 genes as well as in DAPK, but a much lower fraction in all other pathological categories. We discuss the problem to develop diagnostic tests based on complex methylation patterns that make it difficult to classify amplicons as "methylated" or "unmethylated".

APOBEC3 deaminases induce hypermutation in human papillomavirus 16 DNA upon beta interferon stimulation

Apolipoprotein B mRNA-editing catalytic polypeptide 3 (APOBEC3) proteins are interferon (IFN)-inducible antiviral factors that counteract various viruses such as hepatitis B virus (HBV) and human immunodeficiency virus type 1 (HIV-1) by inducing cytidine (C)-to-uracil (U) mutations in viral DNA and inhibiting reverse transcription. However, whether APOBEC3 proteins (A3s) can hypermutate human papillomavirus (HPV) viral DNA and exhibit antiviral activity in human keratinocyte remains unknown. Here we examined the involvement of A3s in the HPV life cycle using cervical keratinocyte W12 cells, which are derived from low-grade lesions and retain episomal HPV16 genomes in their nuclei. We focused on the viral E2 gene as a potential target for A3-mediated hypermutation because this gene is frequently found as a boundary sequence in integrated viral DNA. Treatment of W12 cells with beta interferon (IFN-β) increased expression levels of A3s such as A3A, A3F, and A3G and induced C-to-U conversions in the E2 gene in a manner depending on inhibition of uracil DNA glycosylase. Exogenous expression of A3A and A3G also induced E2 hypermutation in W12 cells. IFN-β-induced hypermutation was blocked by transfection of small interfering RNAs against A3G (and modestly by those against A3A). However, the HPV16 episome level was not affected by overexpression of A3A and A3G in W12 cells. This study demonstrates that endogenous A3s upregulated by IFN-β induce E2 hypermutation of HPV16 in cervical keratinocytes, and a pathogenic consequence of E2 hypermutation is discussed.

Overexpression of p16(INK4a) in urothelial carcinoma in situ is a marker for MAPK-mediated epithelial-mesenchymal transition but is not related to human papillomavirus infection

BACKGROUND

The role of human papillomavirus (HPV) in bladder carcinogenesis remains controversial. Overexpression of p16(INK4a), a surrogate marker for infection with oncogenic HPV in other tumours, has been described for urothelial carcinoma in situ (UCIS). Our goal was therefore to evaluate whether overexpression of p16(INK4a) is associated with HPV infection and to identify mechanisms of p16(INK4a) upregulation in UCIS.

MATERIALS AND METHODS

In 60 tissue specimens from a total of 45 patients (UCIS and controls), we performed p16(INK4a) immunohistochemistry followed by detection and subclassification of HPV DNA. In a subset of samples, we tested for gene amplification of p16(INK4a) applying fluorescence in situ hybridization (FISH). RAS/MAPK signalling and epithelial-mesenchymal transition (EMT) was assessed using immunohistochemistry. Finally, we transfected urothelial carcinoma cells with KRAS and examined the expression of p16(INK4a) as well as markers of EMT.

RESULTS

We found overexpression of p16(INK4a) in 92.6% of UCIS and in all cervical intraepithelial neoplasia (CIN) controls. In contrast, we detected high-risk HPV DNA in 80% of CIN, but none in UCIS. There was no gene amplification of p16(INK4a). High levels of phosphorylated kinases and urokinase plasminogen activator (uPA) and loss of membraneous E-cadherin were detected in UCIS. KRAS transfection of urothelial carcinoma cells led to upregulation of p16(INK4a) and uPA accompanied by loss of E-cadherin that could be inhibited by application of the kinase-inhibitor Sorafenib.

CONCLUSIONS

Our results show that overexpression of p16(INK4a) in UCIS is neither associated with HPV infection nor p16(INK4a) gene amplification but is a consequence of enhanced RAS/MAPK signalling that promotes EMT, possibly due to Sorafenib-sensitive paracrine secretion of the EMT activator uPA. These findings might open a novel therapeutic option for localized but aggressive urothelial cancer.

Human papillomavirus (HPV) upregulates the cellular deubiquitinase UCHL1 to suppress the keratinocyte's innate immune response

Persistent infection of basal keratinocytes with high-risk human papillomavirus (hrHPV) may cause cancer. Keratinocytes are equipped with different pattern recognition receptors (PRRs) but hrHPV has developed ways to dampen their signals resulting in minimal inflammation and evasion of host immunity for sustained periods of time. To understand the mechanisms underlying hrHPV's capacity to evade immunity, we studied PRR signaling in non, newly, and persistently hrHPV-infected keratinocytes. We found that active infection with hrHPV hampered the relay of signals downstream of the PRRs to the nucleus, thereby affecting the production of type-I interferon and pro-inflammatory cytokines and chemokines. This suppression was shown to depend on hrHPV-induced expression of the cellular protein ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) in keratinocytes. UCHL1 accomplished this by inhibiting tumor necrosis factor receptor-associated factor 3 (TRAF3) K63 poly-ubiquitination which lead to lower levels of TRAF3 bound to TANK-binding kinase 1 and a reduced phosphorylation of interferon regulatory factor 3. Furthermore, UCHL1 mediated the degradation of the NF-kappa-B essential modulator with as result the suppression of p65 phosphorylation and canonical NF-κB signaling. We conclude that hrHPV exploits the cellular protein UCHL1 to evade host innate immunity by suppressing PRR-induced keratinocyte-mediated production of interferons, cytokines and chemokines, which normally results in the attraction and activation of an adaptive immune response. This identifies UCHL1 as a negative regulator of PRR-induced immune responses and consequently its virus-increased expression as a strategy for hrHPV to persist.

Evidence for editing of human papillomavirus DNA by APOBEC3 in benign and precancerous lesions

Cytidine deaminases of the APOBEC3 family all have specificity for single-stranded DNA, which may become exposed during replication or transcription of double-stranded DNA. Three human APOBEC3A (hA3A), hA3B, and hA3H genes are expressed in keratinocytes and skin, leading us to determine whether genetic editing of human papillomavirus (HPV) DNA occurred. In a study of HPV1a plantar warts and HPV16 precancerous cervical biopsies, hyperedited HPV1a and HPV16 genomes were found. Strictly analogous results were obtained from transfection experiments with HPV plasmid DNA and the three nuclear localized enzymes: hA3A, hA3C, and hA3H. Thus, stochastic or transient overexpression of APOBEC3 genes may expose the genome to a broad spectrum of mutations that could influence the development of tumors.

Interaction between inflammation and angiogenesis during different stages of cervical carcinogenesis

OBJECTIVE

The primary aim of this study was to investigate the role of angiogenesis and inflammatory cell response in cervical carcinogenesis.

METHODS

Formalin-fixed tissue specimens from 58 uterine cervical specimens (8 CIN1, 14 CIN2, 28 CIN3, and 8 SCC), representing the different stages of cervical carcinogenesis, were immunohistochemically analyzed. Normal cervical tissue specimens were also included as controls. The present study assessed the expression of CD31 and CD105 to evaluate microvessel density (MVD), the macrophage marker CD68 and the panleukocyte marker CD45. In addition, expression of iNOS (inducible Nitric Oxide Synthase) was also evaluated.

RESULTS

MVD, measured by either CD31 or CD105, increased along the continuum from normal epithelium to squamous cell carcinoma, and a significant correlation between the CD105-MVD and the CD31-MVD was observed (r=0.8735; p<0.0001). Furthermore, the number of infiltrating macrophages was significantly associated with progression to malignancy. Interestingly, there was a close positive correlation between macrophage counts and CD105-MVD (r=0.7525; p<0.0001). In striking contrast to the other angiogenic and inflammatory markers tested, iNOS expression was significantly reduced as cervical lesion grade progressed from low to high.

CONCLUSIONS

Our findings demonstrated a positive correlation between neovascularity and macrophage counts, whereas iNOS expression displayed an inverse relationship with macrophage density and tumor progression. Low iNOS expression may modify the function of tumor-infiltrating macrophages toward a malignant phenotype that promotes tumor progression rather than an anti-tumor response.

COX-2 overexpression as a biomarker of early cervical carcinogenesis: a pilot study

BACKGROUND

Recent studies have demonstrated that cyclooxygenase-2 (COX-2) expression is up-regulated in a number of cancers. Selective inhibition of COX-2 offers a potential pharmacological strategy for cancer prevention. The COX-2 isoform is induced in response to inflammatory factors and is expressed in premalignant lesions, including cervical tissues. Few studies have investigated COX-2 expression as a biomarker for early cervical carcinogenesis. In this preliminary study, we assessed the variability of COX-2 overexpression in cervical premalignant lesions.

METHODS

Fifty-two patients were recruited and consented. Paired abnormal and control (normal) cervical biopsies were obtained and evaluated for high-risk human papillomavirus (HPV), inflammation, histopathological diagnosis, and COX-2 protein concentration by ELISA. Paired Student's t-test and general linear regression models were used to compare mean COX-2 protein concentrations among biopsy samples and selected risk variables.

RESULTS

Forty-seven of fifty-two paired biopsies were evaluated. COX-2 protein concentrations were 4.9-fold greater in abnormal biopsies (CIN 1 and CIN 2) than normal biopsies. COX-2 was also significantly increased in inflammation-positive biopsies. No significant association was found between COX-2 levels and HPV high-risk positivity, age, parity, STI history, or hormonal contraceptive use, but the sample size was small.

CONCLUSIONS

These results suggest that COX-2 induction begins in the premalignant phase of cervical carcinogenesis and is correlated with inflammation. A trial using a much larger number of specimens will allow further development of our understanding of COX-2 as a biomarker for use in chemoprevention trials.

Relationship between the expression of telomerase and human papillomavirus infection in invasive uterine cervical carcinoma

Telomerase activity was examined in invasive cervical carcinoma to assess whether it is activated during cervical malignant transformation and to look for its possible association with human papillomavirus (HPV) infection. Histologically confirmed invasive cervical carcinomas and benign cervices were assayed for telomerase activity by using a modified telomere repeat amplification protocol (TRAP). The same cases were subjected to polymerase chain reaction (PCR) detection of HPV by using consensus primers and type-specific (HPV types 16 and 18) primers. Telomerase activity was detected in 40 of 45 (88.9%) invasive cervical carcinomas and 2 (all chronic cervicitis) of 50 (4%) benign cervical lesions. HPV was detected in 36 (24 HPV-16 and 4 HPV-18 cases) of 45 (80%) invasive cervical carcinomas and 20 (11 HPV-16 and 1 HPV-18 cases) of 50 (40%) benign cervical changes. There was a significant correlation between the expression of telomerase with histological grade (omega=0.44, P<0.005), but no correlation was found between telomerase expression and HPV-18 (P>0.05). Although larger sample studies are needed, there seems to be a clear association between telomerase upregulation and HPV status, mainly HPV-16 infection.

Increased phosphorylation of p70 S6 kinase is associated with HPV16 infection in cervical cancer and esophageal cancer

HPV16 E6 interacts with and degrades tumour suppressor protein TSC2 leading to the phosphorylation of p70 S6 kinase. We studied the association of S6 kinase phosphorylation and HPV16 infection in cervical cancer and esophageal cancer. Immunohistochemistry was used to assess phosphorylated S6 kinase (Thr 389) and phosphorylated S6 (Ser235/236) in 140 cervical cancer and 161 esophageal cancer specimens. Immunohistochemical staining for pS6 kinase and pS6 was significantly more frequent in the HPV16-infected cervical cancer specimens than the HPV16-negative specimens. In contrast, the expression of S6 kinase was similar in both HPV16-positive and -negative samples. The phosphorylation of Akt, the key regulator of S6 kinase, was also detected. Our analysis showed that Akt phosphorylation was unaffected by HPV16 infection. These results together with our previous study suggest that HPV16 modifies S6 kinase activation via mechanism, which activates S6 kinase downstream of Akt function.

Upregulation of telomerase (hTERT) is related to the grade of cervical intraepithelial neoplasia, but is not an independent predictor of high-risk human papillomavirus, virus persistence, or disease outcome in cervical cancer

Telomerase activation and telomere maintenance are essential for cell immortalization and represent a rate-limiting step in cancer progression. The E6 oncoprotein of high-risk human papillomavirus (HPV) is known to activate telomerase, but its expression in CIN lesions and its prognostic value in cervical cancer (CC) are still incompletely understood. As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for hTERT (telomerase reverse transcriptase), and tested for HPV using PCR with three primer sets (MY09/11, GP5(+)/GP6(+), SPF). Follow-up data were available from all SCC patients, and 67 CIN lesions had been monitored with serial PCR for HPV after cone treatment. Expression of hTERT was increased in parallel with the grade of CIN, with major up-regulation upon transition to CIN3 (OR 18.81; 95% CI 8.48-41.69; P = 0.0001). Positive hTERT expression was 90% specific indicator of CIN, with 98.7% PPV, but suffers from low sensitivity (57.5%) and NPV (14.3%). hTERT expression was also significantly associated to HR-HPV with OR 3.38 (95% CI 1.90-6.02; P = 0.0001), but this association was confounded by the histological grade (Mantel-Haenszel common OR = 1.83; 95% CI 0.92-3.79; P = 0.086). Expression of hTERT did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic predictor in cervical cancer in univariate or multivariate survival analysis. It was concluded that up-regulation of hTERT was closely associated with HR-HPV, due to activation by the E6 oncoprotein. hTERT is a late marker of cervical carcinogenesis, significantly associated with progression to CIN3. Theoretically, a combination of hTERT assay (showing high SP and PPV) with another test showing high SE and high NPV (e.g. Hybrid Capture 2 for HPV), should provide an ideal screening tool capable of high-performance detection of CIN lesions.

The role of cyclins and cyclins inhibitors in the multistep process of HPV-associated cervical carcinoma

BACKGROUND

Human papillomavirus (HPV) types 16 and 18 are associated with cervical carcinogenesis. This is possibly achieved through an interaction between HPV oncogenic proteins and some cell cycle regulatory genes. However, the exact pathogenetic mechanisms are not well defined yet.

METHODS

We investigated 110 subjects (43 invasive squamous cell carcinoma (ISCC), 38 CIN III, 11 CIN II, 18 CIN I) confirmed to be positive for HPV16 and/or 18 as well as 20 normal cervical tissue (NCT) samples for abnormal expression of cyclin D1, cyclin E, CDK4, cyclin inhibitors (p21 (waf), p27, p16 (INK4A)) and Ki-67 using immunohistochemistry and differential PCR techniques.

RESULTS

There was a significant increase in the expression of Ki-67, cyclin E, CDK4, p16 (INK4A) (p=0.003, 0.001, 0.001) and a significant decrease in p27 (Kip1) from NCT to ISCC (p=0.003). There was a significant correlation between altered expression of p27 (KIP1) and p16(INK4A) (p<0.001), cyclin D1 and CDK4 (p=0.001), cyclin E and p27 (Kip1) (p=0.011) in all studied groups. In ISCC, there was significant relationship between standard clinicopathological prognostic factors and high Ki-67 index , increased cyclin D1 and cyclin E, reduced p27 (Kip1) and p21 (waf).

CONCLUSION

1) Aberrations involving p27 (KIP1), cyclin E, CDK4 and p16 (INK4A) are considered early events in HPV 16 and 18-associated cervical carcinogenesis (CINI & II), whereas cyclin D1 aberrations are late events (CINIII & ISCC) 2) Immunohistochemical tests for p16 (INK4A) and cyclin E could help in early diagnosis of cervical carcinoma 3) Only FIGO stage, cyclin D1, p27 (Kip1) and Ki-67 are independent prognostic factors that might help in predicting outcome of cervical cancer patients.

Over-expression of topoisomerase IIalpha is related to the grade of cervical intraepithelial neoplasia (CIN) and high-risk human papillomavirus (HPV), but does not predict prognosis in cervical cancer or HPV clearance after cone treatment

OBJECTIVE

One of the pathways leading to cervical cancer is a loss of normal cell cycle control. Topoisomerase IIalpha and IIbeta are important nuclear proteins controlling the G2/M checkpoint, and shown to be over-expressed in many human cancers. Their links to oncogenic human papillomavirus (HPV) types and their prognostic value in cervical cancer are practically unexplored.

MATERIAL AND METHODS

As part of our HPV-PathogenISS study, a series of 150 squamous cell carcinomas (SCC) and 152 CIN lesions were examined using immunohistochemical (IHC) staining for topoisomerase IIalpha (topo IIalpha), and tested for HPV using PCR with three primer sets (MY09/11, GP5/GP6, SPF). Follow-up data were available from all SCC patients, and 67 CIN lesions had been monitored with serial PCR for HPV clearance/persistence after cone treatment.

RESULTS

Topo IIalpha expression increased with increasing grade of CIN (p = 0.0001), with the most dramatic up-regulation upon progression from CIN2 to CIN3 and peaking in SCC (OR 16.23; 95%CI 7.89-33.38). Topo IIalpha up-regulation was also significantly associated with HR-HPV detection in univariate analysis (OR = 3.07; 95%CI 1.70-5.52), but was confounded by the histological grade (Mantel-Haenszel common OR = 1.622; 95%CI 0.782-3.365), and by entering both p16(INK4a) (9) and Survivin (33) in the multivariate regression model. Topo IIalpha did not predict clearance/persistence of HR-HPV after treatment of CIN, and it was not a prognostic factor in cervical cancer in either univariate or multivariate analysis.

CONCLUSIONS

Over-expression of topo IIalpha is significantly associated with progression from CIN2 to CIN3, being a late marker of cell proliferation. Its close association with HR-HPV is plausibly explained by the fact that E7 oncoproteins of these HR-HPV (but not LR-HPV) block the normal pRb-mediated inhibition of topo IIalpha by degrading the wild-type Rb.

Telomerase activity as an adjunct to high-risk human papillomavirus types 16 and 18 and cytology screening in cervical cancer

Telomerase is a ribonucleoprotein comprising an RNA template, the telomerase-associated protein and its catalytic subunit, human telomerase reverse transcriptase (hTERT). Telomerase activation is a critical step in cellular immortalisation and development of cancer. Enhanced telomerase activity has been demonstrated in cervical cancer. In the present study telomerase activity and hTERT mRNA expression were evaluated and correlated with the presence of human papillomavirus (HPV) infection and cytological changes in the cervical lesions. Telomerase activity was assayed by telomeric repeat amplification protocol, hTERT mRNA expression by reverse transcriptase polymerase chain reaction and presence of high risk HPV (HR-HPV) infection by polymerase chain reaction. Out of 154 cervical samples of different cytology, 90 (58.44%) were positive for HR-HPV types 16/18, while among 55 normal cervical scrapes, 10 (18.18%) were HPV DNA positive. All 59 invasive cancer samples showed a very high telomerase activity. Among dysplasia, seven (63.6%) mild dysplasia, 18 (100%) of moderate, 20 (100%) of severe dysplasia and 6 (100%) carcinoma in situ (CIS) samples were positive with mild to moderate to high to very high telomerase activity respectively. Seven (12.7%) samples of apparently normal cervical scrapes were weakly positive for telomerase activity. We observed a good correlation (P<0.001) between telomerase activity and HR-HPV 16/18 positivity with a sensitivity of 88.1% for HPV and 100% for telomerase activity. It is suggested that telomerase activity may be used as an adjunct to cytology and HPV DNA testing in triaging women with cervical lesions.

The expression of epidermal growth factor receptor, vascular endothelial growth factor, matrix metalloproteinase-2, and cyclooxygenase-2 in relation to human papilloma viral load and persistence of human papillomavirus after conization with negative margins

The aim of this study was to investigate the correlations between human papillomavirus (HPV) load and vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR), matrix metalloproteinase-2 (MMP-2), and cyclooxygenase-2 (COX-2), and to identify biomarkers that may predict high-risk HPV clearance or persistence after conization with negative margins. The following samples were analyzed: 77 paraffin-embedded specimens from patients with cervical intraepithelial neoplasia (CIN), including 27 CIN 2 conization specimens and 50 CIN 3 conization specimens. Immunohistochemical analysis was performed with antibodies to VEGF, EGFR, MMP-2, and COX-2. Hybrid capture II testing was used to detect HPV DNA. VEGF expression was significantly associated with HPV load (ρ = 0.27186,P= 0.0191), while COX-2 expression was significantly and inversely associated with HPV load (ρ =−0.34309,P= 0.0028). In univariate analysis, HPV load (P= 0.0112) and VEGF expression (P= 0.0274) were significantly associated with high-risk HPV clearance or persistence after conization with negative margins. In multiple regression analysis, high viral load (relative light unit/positive control > 500) and positive VEGF expression were significantly associated with high-risk HPV persistence after conization with negative margins (odds ratio [OR]: 9.915, CI: 1.891–51.994; OR: 6.661, CI: 1.208–36.722, respectively). In conclusion, VEGF expression is related to HPV load, while COX-2 expression is inversely related to HPV load, and immunohistochemical analysis of VEGF expression and HPV viral load are a significant and an independent prognostic indicator of high-risk HPV persistence after conization with negative margins.

Human papillomavirus type 16 E7 up-regulates AKT activity through the retinoblastoma protein

Human papillomaviruses (HPV) are small DNA tumor viruses causally associated with cervical cancer. The early gene product E7 from high-risk HPV is considered the major transforming protein expressed by the virus. Although many functions have been described for E7 in disrupting normal cellular processes, we describe in this study a new cellular target in primary human foreskin keratinocytes (HFK), the serine/threonine kinase AKT. Expression of HPV type 16 E7 in HFK caused inhibition of differentiation, hyperproliferation, and up-regulation of AKT activity in organotypic raft cultures. The ability of E7 to up-regulate AKT activity is dependent on its ability to bind to and inactivate the retinoblastoma (Rb) gene product family of proteins. Furthermore, we show that knocking down Rb alone, with short hairpin RNAs, was sufficient to up-regulate AKT activity in differentiated keratinocytes. Up-regulation of AKT activity and loss of Rb was also observed in HPV-positive cervical high-grade squamous intraepithelial lesions when compared with normal cervical tissue. Together, these data provide evidence linking inactivation of Rb by E7 in the up-regulation of AKT activity during cervical cancer progression.

Germline genetic polymorphisms of CYP1A1, GSTM1 and GSTT1 genes in Indian cervical cancer: Associations with tumor progression, age and human papillomavirus infection

OBJECTIVES

Host genetic factors may play a role in human papillomavirus (HPV)-associated tumorigenesis, although the issue continues to be a focus of much debate. Biotransformation is critical in carcinogenic activity of numerous environmental carcinogens. It is therefore possible that polymorphisms of genes producing functional changes in xenobiotic metabolizing enzymes may be susceptible factors in cervical carcinogenesis. This study looked into possible relationships among these factors.

METHODS

In this case-control study, we analyzed leukocyte DNA from a total of 312 subjects for germline polymorphisms of CYP1A1 (m1 and m2), GSTM1 and GSTT1 at various stages of the cervical tumor progression spectrum, using PCR and RFLP.

RESULTS

Both m1 and m2 polymorphisms of the CYP1A1 gene were more frequent among cases (36.1% for m1 and 38.1% for m2) compared to control subjects (18.2% and 17.6% respectively). The odds ratio of a subject with homozygous CYP1A1 m1 and m2 variant being a case was highest (m1 OR = 4.77 [95% CI = 1.28-17.77]; P = 0.02 and m2 OR = 5.48 [95% CI = 1.49-20.19]; P = 0.011) respectively. The distribution of m1 and m2 CYP1A1 genotypes was also studied as a function of age and in relation to the presence of HPV 16 infection. The risk due to CYP1A1 m1 genotype, when adjusted for HPV status, showed a significantly increased risk (OR = 3.58, 95% CI = 1.88-6.81; P = 0.0001). Similar results were observed in the case of CYP1A1 m2 variant and HPV 16. There was a significant over-representation of both m1 (25.9% vs. 13.9%) and m2 (27.9% vs. 13.3%) polymorphisms in older women (46 years or more). GSTM1 and GSTT1 deletions were also prominent among cases (53.7% and 16.3% respectively) compared to controls (32.7% and 9.7% respectively). A higher proportion of both GSTT1 and GSTM1 deletions were also detected in HPV-16-positive subjects.

CONCLUSIONS

These results suggest that polymorphisms in the CYP1A1, GSTM1 and GSTT1 genes may render women more susceptible to the development of cervical cancer. The association between this susceptibility and the presence of human papillomavirus infection further emphasizes the significance of the genetic polymorphisms.

Semi-quantitative fluorescent PCR analysis identifies PRKAA1 on chromosome 5 as a potential candidate cancer gene of cervical cancer

OBJECTIVE

Comparative genomic hybridization has frequently detected amplification of chromosome 5p in cervical cancer, but candidate cancer genes within the region are rarely known. Therefore, we pursued to identify potential candidate gene related to cervical cancer development.

METHODS

A series of 128 cervical tumor samples were examined by semi-quantitative fluorescent differential PCR for copy number changes on three candidate genes (PRKAA1, CTNND2 and POLS) mapped to chromosome 5p and one gene (ERBIN) mapped to chromosome 5q12.3. The impact of gene copy number was later analyzed in relation to HPV infection, tumor stage or tumor radiosensitivity.

RESULTS

DNA copy numbers of PRKAA1, CTNND2 and ERBIN were significantly different from normal controls (P < 0.05). DNA copy number changes did not correlate with HPV infection, tumor stages or tumor radiosensitivity. Using RT-PCR, PRKAA1 mRNA expression in seven tumor samples with known 5p amplification was amplified from 3- to 15-fold. Over-expression of PRKAA1 was further confirmed by immunohistochemical staining on 125 paraffin-embedded cervical cancer tissues. The expression level in cervical tumor was significantly higher than that in normal epithelium (P < 0.001).

CONCLUSIONS

PRKAA1 gene codes for the catalytic alpha 1 subunit of the AMP-activated protein kinase which is an important cellular metabolic stress regulator. It might assist tumor cells growth under stress. Thus, PRKAA1 may be one of the potential candidate genes for cervical carcinogenesis.

Down-regulated nucleoside diphosphate kinase nm23-H1 expression is unrelated to high-risk human papillomavirus but associated with progression of cervical intraepithelial neoplasia and unfavourable prognosis in cervical cancer

OBJECTIVE

One of the factors leading to an invasive phenotype is the nm23 family of metastases-associated genes. Of the six known members, nm23-H1 is the most frequently studied potential anti-metastatic gene in cervical cancer. However, the possible molecular links to oncogenic human papillomavirus (HPV) are completely unexplored as yet.

MATERIALS AND METHODS

As a part of the HPV-Pathogen Istituto Superiore di Sanità study, a series of 150 squamous cell carcinomas (SCCs) and 152 cervical intraepithelial neoplasia (CIN) lesions were examined by immunohistochemical staining for nm23-H1, and tested for HPV by polymerase chain reaction (PCR) with three sets of primers (MY09/11, GP5(+)/GP6(+) and short PCR fragment). Follow-up data were available on all patients with SCC, and 67 CIN lesions were monitored by serial PCR for clearance or persistence of HPV after cone treatment.

RESULTS

A linear decrease (p = 0.001) was observed in nm23-H1 expression, starting from CIN1 (85% with normal expression), with the most dramatic down regulation on transition from CIN2 (70% normal) to CIN3 (39%) and further to SCC (25%). Reduced expression was associated with CIN3 or cancer at an odds ratio 8.72 (95% confidence interval 4.13 to 18.41). Nm23-H1 was of no use as a marker of the high-risk human papillomavirus (HR-HPV) type, and it did not predict clearance or persistence of HR-HPV after treatment of CIN. Importantly, nm23-H1 expression was a significant prognostic factor in cervical cancer, reduced expression being associated with lower survival (p = 0.022) in univariate analysis. In the multivariate (Cox) regression model, however, only the International Federation of Gynecology and Obstetrics stage (p = 0.001) and age (p = 0.011) remained independent prognostic predictors.

CONCLUSIONS

Down-regulated nm23-H1 expression is markedly associated with progression from CIN2 to CIN3, and predicts poor prognosis in cervical cancer. Nm23-H1 down regulation is probably orchestrated by mechanisms independent of HR-HPV oncoproteins and is possibly related to the emergence of a proteolytic phenotype.

Matrix metalloproteinase-2 (MMP-2) and its tissue inhibitor (TIMP-2) are prognostic factors in cervical cancer, related to invasive disease but not to high-risk human papillomavirus (HPV) or virus persistence after treatment of CIN

OBJECTIVE

Matrix metalloproteinase-2 (MMP-2) and its tissue inhibitor (TIMP-2) are important regulators of cancer invasion and metastasis. Their associations to high-risk (HR) human papillomavirus (HPV) in cervical intra-epithelial neoplasia (CIN) and cervical cancer (CC) are unexplored and their prognostic significance in CC remains controversial.

MATERIALS AND METHODS

As part of our HPV-PathogenISS study, a series of 150 CCs and 152 CIN lesions were examined using immunohistochemical (IHC) staining for MMP-2 and TIMP-2 and tested for HPV using PCR with 3 primer sets (MY09/11, GP5+/GP6+, SPF). Follow-up data were available from all squamous cell carcinoma patients and 67 CIN lesions had been monitored with serial PCR for HPV after cone treatment.

RESULTS

MMP-2 increased with the grade of CIN, with major up-regulation upon transition to invasive cancer (OR 20.78) (95%CI 7.16-60.23) (p=0.0001). TIMP-2 retained its normal expression until CIN3, with dramatic down-regulation in invasive disease (p=0.0001 for trend). Thus, the MMP2:TIMP-2 ratio increased with progressive CIN, exceeding the value 1.0 only in invasive disease. Both MMP-2 and TIMP-2 are highly specific (TIMP-2; 100%) discriminators of CIN with 100% positive predictive value (TIMP-2), but suffer from low sensitivity and negative predictive value. Neither MMP-2 nor TIMP-2 showed any significant association with HR HPV or virus persistence/clearance. TIMP-2 (but not MMP-2) was a significant predictor of survival in univariate (Kaplan-Meier) analysis (p=0.007), but lost its significance in multivariate (Cox) analysis.

CONCLUSION

The activities of MMP-2 and TIMP-2 in cervical carcinogenesis seem to be unrelated to HR-HPV The inverse MMP-2:TIMP-2 ratio is a sign of poor prognosis. A combination of a TIMP-2 assay with another test showing high SE and high NPV (e.g., HCII for HPV) should provide a potential screening tool capable of accurate detection of CIN.

Induction of aromatase expression in cervical carcinomas: effects of endogenous estrogen on cervical cancer cell proliferation

Epidemiologic studies have implicated estrogenic exposure as well as human papilloma virus (HPV) infection in cervical carcinogenesis, and some studies have suggested that estrogen and HPV may play synergistic roles in cervical tumorigenesis. In this study, we report a novel finding that approximately 35% of cervical carcinomas tested (n = 19) express aromatase, the enzyme responsible for converting androgen to estrogen, the rate-limiting and final step in estrogen biosynthesis. On the other hand, no aromatase expression was detected in precancerous (n = 42) or normal cervical (n = 17) tissue samples. Increased aromatase was associated with increases in estrogen receptors (ER-alpha and ER-beta) and a decrease in progesterone receptor levels, suggesting that in situ estrogen signaling via ER may be involved in tumor growth. Stable overexpression of aromatase in HPV+ cervical cancer cells resulted in increased cellular proliferation, anchorage-independent growth, and ER expression and activity. In contrast, little change in ER was observed in HPV- cells. Steroid hormone receptor expression observed in vitro paralleled that seen in cervical carcinomas expressing aromatase. Aromatase overexpression also induced the expression of cyclin D1, proliferating cell nuclear antigen, and the HPV oncogenes, E6 and E7. Furthermore, the data underscores the importance of steroid receptor (estrogen and progesterone receptors) regulation in cervical carcinogenesis. To our knowledge, this is the first report demonstrating the induction of aromatase expression in cervical carcinomas, and opens the possibility that aromatase inhibitors may be potential therapeutic agents in cervical carcinomas expressing aromatase.

Infection of human papillomavirus and overexpression of dihydrodiol dehydrogenase in uterine cervical cancer

OBJECTIVE

To determine the association of human papillomavirus (HPV) infection with the expression of dihydrodiol dehydrogenase (DDH) in uterine cervical cancer (UCC).

METHODS

In situ hybridization (ISH) and immunohistochemistry were applied to examine pathological specimens of 145 patients with UCC.

RESULTS

By ISH, HPV16/18 DNA was detected in 108 (74.5%) UCC cases. DDH expression determined by immunohistochemistry was detected in 81 (75%) lesions among 108 HPV-positive cases. In contrast, of 37 HPV-negative cases, DDH was only detected in 16 (43.2%) of the lesions. A significant correlation was found between DDH expression and the presence of HPV (P < 0.001), FIGO stage (P = 0.004), lymph node involvement (P < 0.001), as well as patients' survival (P = 0.002). In vitro, DDH expression was also found closely associated with HPV infection, and DDH content was proportional to cell sensitivity for cisplatin and doxorubicin.

CONCLUSIONS

HPV infection provokes local inflammation, which can then induce DDH expression and drug resistance in UCC. The detailed biological relationship among HPV infection, expression of DDH and drug resistance, however, remains to be clarified.

Activity profiling of deubiquitinating enzymes in cervical carcinoma biopsies and cell lines

Ubiquitin specific proteases (USPs) regulate the production and recycling of ubiquitin and are thereby critically involved in the control of cell growth, differentiation, and apoptosis. Increasing evidence implicates deregulation of USPs in malignant transformation but there is very little information on the overall and specific activity of USPs in normal and tumor tissues. We have used a chemistry-based functional proteomics approach to profile the activities of individual USPs in biopsies of human papillomavirus (HPV) carrying cervical carcinoma and adjacent normal tissue. To assess the contribution of HPV proteins, USP activity was also compared in HPV positive and negative cervical carcinoma cell lines and HPV E6/E7 immortalized human keratinocytes. The activity of the C-terminal hydrolases UCH-L3 and UCH37 was upregulated in the majority of tumor tissues compared to the adjacent normal tissues. UCH-L1 activity was lower in a significant proportion of the tumors but to a less extent in advanced tumors. In accordance with the relatively low UCH-L1 activity in tumor biopsies, UCH-L1 was detected only in one out of eight cervical carcinoma lines. UCH-L1, UCH-L3, USP7, and USP9X activity was upregulated following HPV E6/E7 immortalization of keratinocytes, suggesting a role of these enzymes in growth transformation.

Quantitative determination of human telomerase reverse transcriptase messenger RNA expression in premalignant cervical lesions and correlation with human papillomavirus load

Expression of human telomerase reverse transcriptase (hTERT) messenger RNA (mRNA) and human papillomavirus (HPV)-16 load were quantified using real-time polymerase chain reaction and correlated with cytological findings and the presence of HPV infection in cervical specimens. Human telomerase reverse transcriptase mRNA expression was evaluated in 15 (20.5%) of 73 specimens of atypical squamous epithelial cells of undetermined significance, in 62 (39.7%) of 156 low-grade squamous intraepithelial lesions (LGSILs), in 49 (96%) of 51 high-grade squamous intraepithelial lesions (HGSILs), and in 9 (20%) of 45 normal samples, whereas viral load was quantified in 52 (89.6%) of 58 samples infected with HPV-16. The mean levels of hTERT mRNA expression were 0.11 in normal tissue, 0.23 in atypical squamous epithelial cells of undetermined significance, 0.75 in LGSILs, and 2.5 in HGSILs. Thus, a significant increase in hTERT mRNA expression was observed with increasing degrees of cervical dysplasia. The HPV-16 load was significantly higher in samples of HGSIL than in those of LGSILs (P < .001). A significant correlation was observed between viral load and quantitative hTERT mRNA expression (r = 0.65; P < .05). Quantitative hTERT mRNA assessment showed 96% sensitivity and 100% negative predictive value for high-grade dysplasia, whereas the specificity and positive predictive value were 72% and 36.2%, respectively. It is suggested that quantitative hTERT has a very high sensitivity and negative predictive value, whereas the observed specificity was moderate, indicating that it cannot be used as a diagnostic marker but may be an adjunct in the management of women with high-grade cervical dysplasia. However, the final diagnosis must rely on the inclusion of clinical evaluation and additional assessment data.

Activation of the ERK/MAP kinase pathway in cervical intraepithelial neoplasia is related to grade of the lesion but not to high-risk human papillomavirus, virus clearance, or prognosis in cervical cancer

We subjected 302 archival samples (150 squamous cell carcinomas [SCCs] and 152 cervical intraepithelial neoplasia [CIN] lesions) to immunohistochemical staining with extracellular signal-regulated kinase-1 (ERK1) antibody and human papillomavirus (HPV) testing with 3 primer sets. Follow-up data were available for all SCC cases and 67 CIN cases. High-risk (HR) HPV types were associated with CIN (odds ratio [OR], 19.12; 95% confidence interval [CI], 2.31-157.81) and SCC (OR, 27.25; 95% CI, 3.28226.09). There was a significant linear relationship between lesion grade and ERK1 staining intensity (P = .0001). ERK1 staining was a 100% specific indicator of CIN, with a 100% positive predictive value, but a poor predictor of HR HPV. ERK1 expression did not predict clearance or persistence of HR HPV after CIN treatment. ERK1 staining did not significantly predict survival in cervical cancer in univariate (P = .915) or multivariate analysis. After adjustment for HR HPV, stage, age, and tumor grade in the Cox regression model, only stage (P = .0001) and age (P = .002) remained independent prognostic factors. ERK1 expression seems to be an early marker of cervical carcinogenesis. ERK1 overexpression is not a specific marker of HR-HPV in CIN and cervical cancer, nor does it predict virus clearance after CIN treatment or disease outcome in cervical cancer.

The effect of methylenetetrahydrofolate reductase polymorphism C677T on cervical cancer in Korean women

OBJECTIVES

Methylenetetrahydrofolate reductase (MTHFR) gene is associated with DNA hypomethylation, an established hallmark of human cancer cells. The aim of this study was to examine the effect of MTHFR polymorphism C677T on cervical carcinogenesis in the context of other environmental factors, such as smoking, parity, and age at the first intercourse.

METHODS

The study subjects were patients who were pathologically diagnosed with cervical neoplasia and who had a positive result for human papillomavirus (N = 462), and they were compared to normal healthy women as normal controls (N = 454). Genotypes of the patients and control samples were assayed by single base primer extension assay using SNapShot assay kit.

RESULTS

Compared with MTHFR C/C, the odds ratio (95% confidence interval) for MTHFR T/T was 1.4 (0.9-2.3) for invasive cervical cancer and 1.3 (0.8-2.3) for cervical intraepithelial neoplasia (CIN) II or III. The risks for invasive cervical cancer were higher with less than 40 years old at diagnosis (2.1, 1.0-4.3), than with over 40 years old at diagnosis (1.2, 0.7-2.2). Current smoking women with early onset with MTHFR T/T had a 4.7 (0.6-36.2) times higher risk of cervical cancer. The risks of MTHFR T/T or C/T also increased for women with an early age of first intercourse or for women with two or more children, as compared with MTHFR C/C.

CONCLUSION

Polymorphisms of MTHFR are associated with a higher risk of developing cervical cancer, and in particular for an early onset of cervical carcinogenesis.

Telomerase and human papillomavirus as diagnostic adjuncts for cervical dysplasia and carcinoma

Telomerase and human papillomavirus (HPV) DNA were evaluated as potential markers of high-grade dysplasia in cervical cytological specimens. Cytology specimens were collected from patients at the time of colposcopic evaluation for management of a previous abnormal cytology test result. Telomerase activity was evaluated by the telomeric repeat amplification protocol (TRAP), and HPV DNA was detected by polymerase chain reaction with L1 consensus-sequence primers and filter hybridization genotyping. Telomerase was detected in 8 of 97 (8.2%) cases with normal cytology or benign cellular changes, in 7 of 98 (7.1%) cases of atypical squamous cells of undetermined significance (ASCUS), in 3 of 95 (3.2%) cases of low-grade squamous intraepithelial lesion (LSIL), and in 17 of 48 (35.4%) cases with high-grade squamous intraepithelial lesion (HSIL). High-risk HPVs were detected in 23 of 97 (23.7%) cases with normal/reactive cellular changes (RCC) cytology, in 28 of 98 (28.6%) cases of ASCUS, in 69 of 95 (72.6%) cases of LSIL, and in 35 of 48 (72.9%) cases of HSIL. Telomerase expression did not correlate with the detection of high-risk HPVs in any cytological diagnostic categories. Telomerase and HPV test results of cytological specimens were correlated with the histological diagnoses of concurrent cervical biopsy specimens. Telomerase showed a sensitivity of 29.9% and a specificity of 94.0% for biopsy-confirmed cervical intraepithelial neoplasia (CIN) II/III. In contrast, high-risk HPVs were detected in 70.1% of cases with underlying CIN II/III, with a specificity of 62.5%. A relatively high proportion of normal/RCC or ASCUS cases with telomerase-positive test results had underlying high-grade dysplasia on cervical biopsy. Thus, technical and practical limitations of the TRAP assay in cervical cytology specimens limit the practical application of telomerase as a diagnostic adjunct in cervical cytopathology.

Telomerase activation and human papillomavirus infection in invasive uterine cervical carcinoma in a set of Malaysian patients

AIM

Telomerase activity was studied in invasive uterine cervical carcinoma to assess whether it was activated during cervical malignant transformation and to look for a possible association with human papillomavirus (HPV) infection in a set of Malaysian patients.

METHODS

Histologically confirmed invasive cervical carcinoma and benign cervices were assayed for telomerase activity using a commercial telomerase polymerase chain reaction (PCR) enzyme linked immunosorbent assay kit. The same cases were subjected to PCR detection of HPV using type specific (HPV types 6b, 11, 16, and 18) followed by L1 open reading frame (ORF) consensus primers.

RESULTS

HPV was detected in 18 (13 HPV-16, one HPV-6b, four only L1 ORF) of 20 invasive cervical carcinoma and one (only L1 ORF) of 19 benign cervices. Raised telomerase activity (A(450 nm) > 0.215) was detected in 11 cervical carcinomas, with A(450 nm) ranging between 0.238 and 21.790 (mean, 3.952) in positive squamous carcinomas, whereas A(450 nm) was only 0.222 in the one positive adenosquamous carcinoma. Five of 11 cervical carcinomas in stage I, three of six in stage II, both in stage III, and the only case in stage IV showed telomerase activation. Increased telomerase activity was noted in five of the 12 lymph node negative, five of the seven lymph node status unknown cases, and the one case with presumed lymph node metastasis. Ten of 18 HPV positive and one of two HPV negative cervical carcinomas showed telomerase upregulation.

CONCLUSIONS

Telomerase is activated in invasive cervical carcinoma. Although larger studies are needed, there seems to be no clear association between telomerase upregulation and HPV status, although there is a suggestion of increased telomerase activity in squamous carcinomas and late stage disease.

Telomerase activity in condyloma acuminatum tissue with different HPV types

The telomerase activity in condyloma acuminatum (CA) tissue with human papillomavirus (HPV) types of 6/11 and 16/18 was detected to investigate the function of telomerase in the occurrence, development and carcinogenesis of genital CA. Forty-two biopsies from patients with genital CA and 30 control tissue samples were tested for telomerase activity, HPV presence and types. The telomerase activity was determined by modified telomerase repeat amplification protocol (TRAP) assay and HPV typing by polymerase chain reaction (PCR) with typing-specific primers. Results showed that HPV-DNA was negative and the expression rate of telomerase was 16.7% in all normal skin samples. All CA samples were positive for HPV (6/11 type was found in 32 cases, 16/18 in 3 and mixed type in 7). Telomerase activity was detectable in all CA patients. The telomerase activity in CA of 16/18 type was apparently higher than in CA of 6/11 type. It was concluded that the hyperplasia in CA might be increased as a result of HPV infection, suggesting that the activation of telomerase by HPV, especially by 16/18 type may play a role in the etiology and carcinogenesis of genital CA.

Gene amplification and expression of the DNA repair enzyme, N-methylpurine-DNA glycosylase (MPG) in HPV-infected cervical neoplasias

BACKGROUND

Lethal and mutagenic damages of DNA is caused by a variety of agents including viruses. It is known that HPV is one of the major causes of cervical carcinogenesis and that cells eliminate DNA lesions with DNA repair enzymes. However, the role of N-methylpurine-DNA glycosylase (MPG) is not known in the development of cervical cancer.

MATERIALS AND METHODS

Multiplex polymerase chain reaction (PCR) was used for the detection and typing of HPV in the biopsy. Gene amplification of MPG was measured by a PCR-based assay. The mRNA levels of MPG were determined by reverse transcription-PCR using hypoxanthine-guanine phosphoribosyl transferase as the reference gene. An immunohistochemical technique was used to examine the distribution of MPG in the tissues.

RESULTS

Of 68 Korean cervical neoplasia patients, 86.8% showed HPV infection. High-risk HPV 16/18 were the most prevalent but positive only in 47.3% of the invasive cancer patients. Gene amplification of MPG was significantly increased in high-risk HPV-infected tissues as compared to low-risk HPV-infected and normal tissues (p < 0.05). The mRNA levels of MPG were higher in HPV-infected invasive carcinoma than normal cervical tissues. Immunohistochemical staining revealed that the intracellular expression and distribution (localization) of MPG altered in the cervical neoplasia. Interestingly, MPG expression in CIN III and invasive carcinoma (IC) was much higher than normal and CIN I. Granular positivity of MPG was notable in the perinuclear regions of the cytoplasm in HPV-infected invasive cancer.

CONCLUSION

This is the first report on MPG expression in cervical neoplasia. Our results indicate that the gene amplification and expression of MPG were increased in high-risk HPV-infected cervical neoplasias and the intracellular distribution of MPG protein was altered, suggesting a role of MPG in carcinogenesis.

Relationship between telomerase activation and HPV 16/18 oncogene expression in squamous intraepithelial lesions and squamous cell carcinomas of the uterine cervix

SILs (squamous intraepithelial lesions) comprise a wide spectrum of clinically and biologically heterogeneous lesions ranging from benign proliferations to precancerous lesions. Telomerase activation plays a critical role in cellular immortalization and might be important for malignant progression. The viral oncogenes E6 and E7 are the principal transforming genes of high-risk HPVs and are important in HPV-associated immortalization and neoplastic transformation. In this study we investigated the relationship between telomerase activity, telomerase RNA, and HPV 16/18 oncogene expression in low- and high-grade SILs and SCCs (squamous cell carcinomas) of the cervix uteri. Telomerase activity was examined by the TRAP-assay and expression of the telomerase RNA (hTR) and HPV 16/18 E6/E7 oncogenes by RNA/RNA-in situ hybridization (ISH). The associated HPV-type was determined by PCR. Telomerase activity was observed in 25/29 (86%) SCCs, 31/41 (76%) high-grade SILs, 6/14 (43%) low-grade SILs, and 1/28 (3.6%) normal cervical tissues. Expression of hTR and viral oncogenes increased significantly with histopathologic severity of the lesion (p < 0.0001). A correlation was found between telomerase activity and intensity of viral oncogene expression. These findings suggest that telomerase activation occurs early in cervical carcinogenesis and is predominantly found in high-grade SILs and cervical SCCs. Our findings support current experimental data that suggest that telomerase is at least partially activated by viral oncogenes of high-risk HPV types. Telomerase activity with concomitant strong viral oncogene expression might therefore characterize a subset of lesions that are at risk for malignant progression.

Telomerase activity in Papanicolaou smear-negative exfoliated cervical cells and its association with lesions and oncogenic human papillomaviruses

OBJECTIVE

The goal of this study was to evaluate telomerase activity in exfoliated cervical cells and its association with cytology, pathology, and human papillomavirus (HPV).

METHODS

Telomerase activity and HPV DNA sequences were examined in the exfoliated cervical cells from a general population of 245 women aged more than 30 years undergoing routine cervical screening by Papanicolaou smear. The women who were found to have telomerase activity or abnormal cytology in their exfoliated cervical cells were examined for cervical lesions by colposcopy and biopsy.

RESULTS

Cytology for our population (mean, 56 years) revealed only one abnormal smear (1/245, 0.4%), in which a cervical intraepithelial neoplasia grade I (CIN I) lesion was found. The exfoliated cervical cells used to prepare the smear were negative for telomerase and contained low-risk HPV DNA. Telomerase activity was found in 16 exfoliated cell samples (16/245, 6.5%); high-risk HPV DNA was found in 9 of these samples (9/16, 56%) and 9 of the biopsy specimens that could be evaluated from patients testing positive for telomerase revealed CIN I lesions (9/11, 82%).

CONCLUSIONS

Telomerase activity is often associated with high-risk HPV infection and it is suggested that telomerase assay can help to detect occult cervical lesions.

Combined analysis of germline polymorphisms of p53, GSTM1, GSTT1, CYP1A1, and CYP2E1: relation to the incidence rate of cervical carcinoma

BACKGROUND

The authors established the genotype frequencies of cytochrome P450 (CYP1A1/MspI, CYP2E1/PstI, and CYP2E1/DraI), glutathione-S-transferase (GSTM1 and GSTT1), and p53 (exon 4/AcclI and intron 3/16-base pair duplication) gene polymorphisms in cervical carcinoma patients and controls and evaluated the association between the specific genotype or genotype combinations of these polymorphisms and the risk of cervical carcinoma.

METHODS

In this case-control study, the genotypes of 181 human papillomavirus (HPV)-16 or HPV-18 positive cervical carcinoma patients and 1-to-1 age-matched controls were determined using a polymerase chain reaction-based technique.

RESULTS

Among these polymorphisms, the individuals carrying arginine/proline genotypes of p53 showed a 9.5-fold increase of cervical carcinoma risk (95% confidence interval [CI], 4.9-18.6) compared with those individuals carrying arginine/arginine genotypes. The frequency of overall GSTT1 null genotypes also was significantly higher in cervical carcinoma patients compared with that of GSTT1 positive genotypes (P = 0.003; odds ratio [OR] = 1.9; 95% CI, 1.2-2.9). The genotype combination of p53 and GST played a more important role in describing the relative risk of cervical carcinoma. The individuals carrying both the arginine/proline genotype of p53 and the null genotype of GSTT1 showed a 3.5-fold increase of cervical carcinoma risk (95% CI, 1.8-7.1) compared with those individuals carrying both the arginine/arginine genotype of p53 and the GSTT1 positive genotype. In the patients who were stratified into the two age groups, the null genotypes of GSTT1 (69.1% vs. 45.5%; P = 0.016) and GSTM1 (61.8% vs. 40.0%; P = 0.028) in cervical carcinoma were significantly overrepresented in the younger age subgroup (age 40 years or younger) compared with those of controls. Especially in this age group, the individuals carrying both null genotypes of GSTT1 and GSTM1 showed a 17.8-fold increase of cervical carcinoma risk (95% CI, 2.2-141.0) compared with the individuals carrying both positive genotypes of GSTT1 and GSTM1.

CONCLUSIONS

The results of the current study suggested that the arginine/proline genotype of p53, independently or in conjunction with the GSTT1 null genotype, could affect the genetic susceptibility for cervical carcinoma, and HPV positive women carrying both null genotypes of GSTT1 and GSTM1 have an increased risk of cervical carcinoma developing before age 40 years.

Anti-estrogenic activities of indole-3-carbinol in cervical cells: implication for prevention of cervical cancer

BACKGROUND

Cervical cancer constitutes the second most common cancer in women. Estrogen promotes development of cervical cancer in cells infected with high risk human papillomaviruses (HPVs). We asked whether the phytochemical indole-3-carbinol (I3C) has anti-estrogenic activities in cervical cells with the goal of preventing cancer in HPV infected cells.

MATERIALS AND METHODS

Using the cervical cancer cell line CaSki, we evaluated expression of HPV and cytochrome p450 (CYP) enzymes by Northern, RNase protection or quantitative RT-PCR. I3C binding to estrogen receptor was measured by competition with estradiol. Estrogen metabolites were measured by gas chromarography-mass spectrometry (GC-MS).

RESULTS

Estradiol increased expression of HPV oncogenes whereas I3C and the estrogen metabolite 2-hydroxyestrone (2-OHE) abrogated the estrogen-increased expression of HPV oncogenes. Both I3C and 2-OHE competed with estradiol for estrogen receptor binding. I3C enhanced gene expression of CYP enzymes responsible for 2-hydroxylation of estrogen, and induced the formation of 2-OHE.

CONCLUSION

I3C has anti-estrogenic activities which should prevent cancer in cervical cells.

Telomerase activity in thymomas and mammary gland adenocarcinomas induced by polyoma virus in AKR mice

Telomerase is an enzyme that stabilizes telomere length in transformed cells and tumors. Its role in tumor development is far from clear. In this paper, a new experimental model to study telomerase activity during tumorigenesis is presented. After infection with Polyoma virus, AKR mice developed thymomas and mammary gland adenocarcinomas. Polyoma antigens were observed by the peroxidase-antiperoxidase technique on tissue sections, and by Western blot on tumor extracts. The TRAP assay was performed to detect telomerase activity. It was not present in normal mammary gland, but it was positive in mammary gland adenocarcinomas. A different pattern was seen in thymic tissues: normal thymus had higher telomerase activity than thymomas. The incubation of thymoma extracts with normal thymus extracts decreased telomerase activity in the latter. These results demonstrate two different patterns of telomerase activity in tumors induced by Polyoma virus, and suggest the presence of telomerase inhibitory factors in thymomas.

Telomerase activation in cervical cancer

It has been hypothesized that infection with high-risk human papillomaviruses (HPVs), in conjunction with other cellular events, plays a critical role in the development of cervical cancer. Activation of telomerase, a ribonucleoprotein enzyme complex that synthesizes telomere repeats, has been associated with acquisition of the immortal phenotype in vitro and is commonly observed in human cancers. In this study, we have examined 10 high-grade cervical cancers for telomerase activity and for the presence of HPV. Telomerase activity was detected in all of the cancers but in none of the paired histopathologically normal uterine tissues or in normal cervical epithelium. Analysis of these same tissues for HPV nucleic acids by polymerase chain reaction (PCR) using primers from the HPV L1 and E6 open reading frames demonstrated that 7 of 10 cancers were positive for HPV, 3 for HPV type 16 (HPV-16), and 4 for HPV-18. In one case, HPV-16 was detected in histopathologically normal uterine tissue, the same type as that detected in the cancer from the same patient. HPV DNA was not detected in 3 of 10 cancers. These results indicate that telomerase activation is common in high-grade cervical cancers and suggests that telomerase activity may be a useful diagnostic marker for the disease.

Cathepsin E expression by normal and premalignant cervical epithelium

We have investigated the expression of the aspartic proteinase cathepsin E and HLA-DR and the presence of HPV16 in normal squamous epithelium (n = 8) and low-grade (n = 21) and high-grade (n = 14) intraepithelial squamous lesions of the uterine cervix. Immunohistochemistry of cervical biopsies revealed that up-regulation of cathepsin E expression was related to increasing severity of the cervical intraepithelial neoplasia (CIN). Up-regulation of protein was associated with increased message as assessed by in situ hybridization. Langerhans cells and the majority of koilocytes did not express detectable cathepsin E levels. Although there was also an up-regulation of HLA-DR expression by cervical keratinocytes in cervical intraepithelial neoplasia lesions, as determined by immunohistochemistry, no significant correlation was found between HLA-DR and cathepsin E expression in these lesions; neither was expression of cathepsin E correlated to the presence of HPV16, detected by polymerase chain reaction. The expression of cathepsin E, an aspartic proteinase that is reported to play a role in antigen processing for presentation by class II major histocompatibility complex molecules, is associated with cellular dedifferentiation in cervical intraepithelial neoplasia.