Prevalence of Human Papillomavirus (HPV) and HPV Type Distribution in Penile Samples in Young Men in Denmark: Results 10 Years After Implementation of a Girls-Only HPV Vaccination Program.

BACKGROUND: In Denmark, a girls-only human papillomavirus (HPV) vaccination program was initiated in 2008-2009. The study aim was to assess the HPV prevalence and type distribution in younger men prior to HPV vaccination in men. METHODS: The study population was younger men who attended information days regarding military service. At random days (2019-2020), 280 men were included. We collected questionnaire data regarding risk factors for HPV infection and a penile swab for HPV testing. We compared results in this study with those from a previous study of young men (2006-2007). RESULTS: The majority of participants (94%) were 18-20 years old. The median number of lifetime sexual partners was 4. Altogether, 130 men (46.4%) were HPV positive. No infections with HPV types 6, 11, 16, 18, 31, and 45 were detected. The most frequent type was HPV-51 (detected in 11.1%). Comparison showed that the odds of high-risk HPV type infection were higher in 2019-2020 (prevalence odds ratio [POR], 1.7 [95% confidence interval {CI}, 1.1-2.7]) compared with 2006-2007. In contrast, the odds were lower (POR, 0.3 [95% CI, .1-.6]) for HPV types targeted by the 9-valent HPV vaccine. CONCLUSIONS: The multicohort girls-only vaccination program has to a large degree protected young men against the HPV types included in the licensed vaccines. This does not speak against gender-neutral vaccination as the HPV prevalence is still high, although consisting largely of less carcinogenic HPV types.

Time trends in prevalence of p16 positivity and combined HPV/p16 positivity in a large cohort of Danish vulvar cancer patients.

Vulvar cancer is rare, but causes substantial morbidity in affected patients. A subset of vulvar cancers is caused by high-risk human papillomavirus (hrHPV), which primarily exerts its oncogenic effect through upregulation of tumor suppressor protein p16. Tumors positive for both hrHPV and p16 (double positive) are assumed to be HPV-driven, but only few large studies have investigated the combined prevalence of hrHPV and p16 positivity in vulvar cancer over time. In this Danish cross-sectional study, we assessed the prevalence of p16 positivity and double positivity for hrHPV and p16 in a large sample of vulvar squamous cell carcinomas (VSCCs) diagnosed during 1990 to 2017. In a nationwide register, we identified VSCCs from 13 hospitals across Denmark, and collected archival tumor tissue for hrHPV testing with INNO-LiPA and immunohistochemical p16 staining. We calculated the prevalence of hrHPV, p16 positivity and double positivity according to time, age and histological subtype and evaluated time trends through estimated annual percentage changes. We included 1278 VSCCs. Overall, 35.0% (95% confidence interval [CI]: 32.4-37.6) were positive for p16 and 31.0% (95% CI: 28.4-33.5) were positive for both hrHPV and p16. The prevalence of p16 positivity and double positivity increased over time, both in women aged ≤59 and ≥60 years. The double positive prevalence was higher in nonkeratinizing (60.7%) and warty/basaloid VSCCs (67.5%) than in keratinizing (16.1%) and verrucous VSCCs (5.0%). These results indicate that approximately one-third of vulvar cancers were caused by hrHPV infection, supporting a substantial preventive potential of the HPV vaccine.

Quality Control of Biospecimens in a Danish Clinical Cytology Biobank.

Introduction: Based on the experience from a Swedish biobank, we established a clinical cervical cytology biobank and adapted it to a Danish setting. The aim of the present study was to validate the biobank material regarding quality and quantity, to determine the usefulness of the material for future diagnostics and biomarker testing. Methods: Cervical cytology samples collected in ThinPrep were analyzed before and after biobanking using p16/ki-67 dual staining, a human papillomavirus (HPV) DNA test (Cobas), and a test for HPV messenger RNA (mRNA; Aptima). The concordance of the test results before and after biobanking was assessed. We also evaluated the morphology before and after biobanking and did additional tests on the biobanked material to qualify the usefulness of the material (library preparation for next-generation sequencing [NGS], reverse transcription-polymerase chain reaction [RT-PCR], and the Inno-Lipa HPV genotyping test). Results: For the Cobas HPV test, the concordance was 92% (122/133), and for the Inno-Lipa test (30 samples), it was 100%. For the Aptima assay, the concordance was a little lower, 84% (42/50). The morphology of the cell was well preserved, and the concordance of the p16/ki-67 dual staining was 88% (37/42). The functional tests showed that DNA-based NGS libraries (TST15 panel; Illumina) had good quality parameters. However, with the RT-PCR, 12% of the samples showed poor quality and a too low input amount for the analysis. Conclusion: The quality of the biobanked samples is high, and the material is suitable for testing of DNA, RNA, and protein. However, for testing of specific biomarkers, pilot studies are recommended to ensure sufficient input amount and quality of the material, especially for RNA-based studies.

Changes in HPV prevalence in Danish women with vulvar cancer during 28 years - A nationwide study of >1300 cancer cases.

OBJECTIVE: A substantial proportion of vulvar cancers are caused by high-risk human papillomavirus (hrHPV), but hrHPV prevalence in vulvar cancer has mainly been investigated in smaller studies which did not evaluate time trends. Our aim was to assess hrHPV prevalence in >1300 Danish vulvar cancers diagnosed during 1990-2017, including changes in hrHPV prevalence over time. METHODS: In a nationwide pathology register, we identified women diagnosed with vulvar cancer at thirteen hospitals from all Danish regions. Archival tumor tissue was collected from local repositories and, upon pathology review, sent to a central laboratory for HPV testing using INNO-LiPA. We calculated hrHPV prevalence according to time, age and histology, and evaluated the overall and age-specific estimated annual percentage change (EAPC). RESULTS: We included 1308 vulvar cancer cases, with a median age of 72 years at diagnosis. The overall hrHPV prevalence was 52.0% (95% CI: 49.3-54.7). HPV types 16/18 were found in 39.6% of cases, whereas nine-valent HPV (9vHPV) vaccine types 16, 18, 31, 33, 45, 52, and 58 were found in 50.8%. The hrHPV prevalence showed an increasing trend over time, with an EAPC of 0.35% (95% CI: 0.00-0.71). The hrHPV prevalence was higher in younger women throughout the study period, and increasing trends over time were seen in both older (age ≥ 60) and younger (age < 60) women. The hrHPV prevalence was higher in non-keratinizing (71.0%) and warty/basaloid (78.0%) carcinomas than in keratinizing (39.4%) and verrucous (36.4%) carcinomas. CONCLUSIONS: Our results indicate that the 9vHPV vaccine could potentially prevent a substantial proportion of vulvar cancers in Denmark.

Clinical performance and acceptability of self-collected vaginal and urine samples compared with clinician-taken cervical samples for HPV testing among women referred for colposcopy. A cross-sectional study.

OBJECTIVES: To increase effectiveness of the cervical cancer screening program, self-sampling can be an option. Both self-collected vaginal samples (SCV) and urine samples may be useful alternatives to clinician-taken cervical samples (CS). DESIGN: Cross-sectional study. SETTING: Colposcopy clinic. PARTICIPANTS: Women (n=305) referred to colposcopy after abnormal cervical screening result or conditions like postcoital bleeding. INTERVENTION: All women self-collected a urine and a vaginal sample prior to colposcopy, where a CS and biopsies were taken. All samples were tested for high-risk human papillomavirus (HPV) using the Cobas HPV assay. The gold standard was histology diagnoses (CIN2+/CIN3+) from biopsies obtained at the same examination. PRIMARY OUTCOME: Absolute and relative sensitivity and specificity of HPV testing on SCV and urine to detect CIN2+/CIN3+ compared with the CS. SECONDARY OUTCOME: The acceptability by women of self-sampling. RESULTS: Both the vaginal and urine sample were comparable to the CS in identifying severe intraepithelial neoplasia (CIN2+/CIN3+). Absolute sensitivity ranged from 93% for urine samples to 96% for SCV for detecting CIN2+, which is comparable to the sensitivity of CS (overlapping 95% CI).The relative sensitivity for detecting CIN2+ was 1.00 (95% CI 0.96 to 1.04) for SCV and 0.96 (95% CI 0.91 to 1.03) for urine samples. At CIN3+, the relative sensitivity was 1.00 (95% CI 0.96 to 1.08) and 0.97 (95% CI 0.89 to 1.07) for SCV and urine samples, respectively. There were no statistical differences between the self-collected samples and the CS (McNemar's test >0.05). The relative specificity was also similar (1.03 (95% CI 0.95 to 1.12) for SCV and 0.98 (95% CI 0.89 to 1.09) for urine samples) (McNemar's test >0.05).The acceptability of self-sampling was evaluated by questionnaire. The women found the instructions on sample collection easy to understand and were positive about self-sampling with a preference for the urine sample. CONCLUSION: Self-sampling by SCV and urine is a clinically safe alternative to CS with a high degree of acceptability.

Benefits and potential harms of human papillomavirus (HPV)-based cervical cancer screening: A real-world comparison of HPV testing versus cytology.

INTRODUCTION: Human papillomavirus (HPV) testing as the primary cervical cancer screening method is implemented in several countries. We report data from the first round of a large Danish pilot implementation of HPV-based screening. Our aim was to compare colposcopy referrals, detection of high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer, and positive predictive value (PPV) of colposcopy referral in HPV vs cytology-based screening. MATERIAL AND METHODS: From May 2017 to October 2018, women aged 30-59 years attending cervical cancer screening in the uptake area of the Department of Pathology, Vejle Hospital, Region of Southern Denmark were screened by primary HPV testing (n = 16 067) or primary cytology (n = 23 981) depending on municipality of residence. In the HPV group, women with HPV16/18, or other high-risk HPV types and abnormal cytology, were referred to immediate colposcopy. Women with other high-risk HPV types and normal cytology were invited for repeat screening with HPV test and cytology after 12 months. From a nationwide pathology register, we obtained information on screening results and subsequent histological diagnoses during up to 2.9 years after the first screen. PPVs included diagnoses within 1 year after referral. RESULTS: In the HPV group, 3.7% were referred to immediate colposcopy and 2.8% were referred at the 12-month repeat screening. The total referral to colposcopy was higher in the HPV (6.6%) than cytology group (2.1%) (age-adjusted relative referral = 3.05, 95% confidence interval [CI] 2.75-3.38). The detection of CIN3+ was higher in the HPV (1.5%) than the cytology group (0.8%) (age-adjusted relative detection = 1.88, 95% CI 1.56-2.28). The probability of CIN3+ among women referred to colposcopy (= PPV) was lower in the HPV (21.1%; 95% CI 18.7%-23.7%) than the cytology group (34.6%; 95% CI 30.7%-38.9%). In the HPV group, the PPV was lower among women referred at repeat screening (12.1%) than among women referred immediately (27.8%). CONCLUSIONS: Compared with cytology-based screening, HPV-based screening provided a 90% increased CIN3+ detection at the cost of a threefold increase in colposcopy referrals, when considering complete data from the prevalence round. Our findings support implementation of HPV-based screening in Denmark, but modifications of screening algorithms may be warranted to decrease unnecessary colposcopy referrals.

Clinical Performance of Human Papillomavirus (HPV) Testing versus Cytology for Cervical Cancer Screening: Results of a Large Danish Implementation Study.

BACKGROUND: Human papillomavirus (HPV) testing is increasingly used as the primary cervical cancer screening test. In a large pilot implementation, we compared participation, referrals and detection of high-grade cervical intraepithelial neoplasia (CIN) in HPV- versus cytology-based cervical cancer screening. METHODS: The implementation was embedded into the routine screening program at Lillebaelt Hospital, Department of Pathology, Vejle, Denmark. Based on the area of residence, women aged 30-59 years were screened by either HPV testing (with HPV16/18 genotyping and cytology triage) or cytology (with HPV triage for minor abnormalities). Our analysis includes women invited or screened during May 2017-May 2018 (invited: n=35,081; screened: n=28,352) with 6 months of follow-up. Information on screening results and sociodemographic characteristics were obtained from registers. Using logistic regression, we estimated odds ratios (ORs) with 95% confidence intervals (CIs) of participation, referral and CIN3+-detection in HPV- versus cytology-based screening, adjusting for sociodemographic characteristics. RESULTS: Participation was virtually identical in the HPV- and cytology group (58.4% vs 58.8%; ORadjusted=0.97, 95% CI, 0.93-1.01). Referral to colposcopy was more common in the HPV- than cytology group (3.8% vs 2.1%; ORadjusted=1.88, 95% CI, 1.63-2.17). More cases of CIN3+ were detected in the HPV- than cytology group (1.0% vs 0.7%, ORadjusted=1.47; 95% CI, 1.13-1.91). CONCLUSION: Participation did not differ between HPV- and cytology-based screening. HPV-based screening detected more cases of CIN3+, but in this initial screening round also led to more colposcopies than cytology-based screening.

The clinical importance of BRCAness in a population-based cohort of Danish epithelial ovarian cancer.

OBJECTIVE: Germline mutations in BRCA1/2 genes predict improved survival and sensitivity to treatment with poly(adenosine-diphosphate-ribose) polymerase inhibitors in epithelial ovarian carcinoma. The prognostic importance of other genetic alterations leading to homologous recombination deficiency, collectively BRCAness phenotype, is unresolved. The aim was to analyze the distribution of homologous recombination deficiency in epithelial ovarian carcinoma caused by mutations in a panel of homologous recombination genes (including BRCA1/2) or epigenetic alterations. A further aim was to investigate the prognostic importance of homologous recombination deficiency, the BRCAness phenotype. METHODS: We assessed 380 patient specimens from a Danish population-based epithelial ovarian carcinoma cohort for germline and somatic mutations in 18 different homologous recombination genes, including BRCA1 and BRCA2, using next generation sequencing. Epigenetic alteration due to BRCA1 hypermethylation was assessed by pyrosequencing and BRCA1 protein expression was evaluated by immunohistochemistry. RESULTS: Seventeen percent of patients with epithelial ovarian carcinoma carried a germline (9.8%) and/or somatic (6.3%) mutation in 12 (BRCA1, BRCA2, CHEK2, ATM, RAD51D, EMSY, PALB2, BRIP1, ERCC1, RAD50, ATR, RAD51C) of 18 sequenced homologous recombination genes. The homologous recombination mutation rate was similar among the different histologic subtypes, however the type of mutation (BRCA1/2 and other homologous recombination mutations) differed, p=4×10-4. BRCA1 hypermethylation was present in 7.4% of patient specimens for a total BRCAness phenotype of 23.9%. The BRCAness phenotype was associated with improved overall survival in the high-grade serous carcinoma subgroup with a median overall survival of 4.4 years (95% CI 3.0 to 5.3) versus 2.2 years (95% CI 1.9 to 2.4) in BRCAness wildtype, p=0.0002. Multivariate analysis confirmed an independent prognostic value of the BRCAness phenotype among the high-grade serous carcinoma subgroup, hazard ratio 0.65 (95% CI 0.47 to 0.92), p=0.014. CONCLUSIONS: The BRCAness phenotype is present in almost one-fourth of epithelial ovarian carcinoma and holds important prognostic information. The implications of our findings in relation to poly(adenosine-diphosphate-ribose) polymerase inhibitor treatment call for further investigation.

Seminal human papillomavirus originates from the body surface and is not a frequent aetiological factor in azoospermia.

Human papillomavirus (HPV) DNA has been detected in the testis tissue of 6.5% of 185 men with non-obstructive azoospermia (NOA). Others have suggested that seminal HPV originates from contamination from the genital skin and mucosa. One hundred unselected azoospermic men and 43 normal men undergoing vasectomy were recruited. Testicular biopsies for HPV examination were collected from all the men. Additionally, the normal men undergoing vasectomy delivered a semen sample and had a swab for HPV examination taken from the genital skin before vasectomy. A piece of each Vas deferens obtained during the vasectomy was examined for the presence of HPV. Two of the primarily azoospermic men were shown to have cryptozoospermia. It was not possible to detect HPV in the testis tissue of any of the included 98 azoospermic men or the 43 proven fertile men. In the proven fertile men, HPV DNA was detected in the semen of 15 men (35%), on the genital skin of 28 men (65%), and in the Vas deferens in three cases (7%). In 13 (87%) men with HPV-positive semen samples, HPV DNA was also detected in the skin swabs, and in 11 men (73%), identical HPV genotypes were found in the two locations.

Combination of real-time PCR and sequencing to detect multiple clinically relevant genetic variations in the lactase gene.

BACKGROUND: Lactase persistence is an autosomal dominant trait commonly distributed in Europe as well as some parts of east Africa and the Arabian Peninsula. Using real-time PCR to detect the -13910C > T variant common in the European population is a reliable analysis although other variants in the probe-binding site may cause errors in analysis. The aim of this study was to determine the prevalence of the variants in a Danish cohort examined for lactose intolerance as well as to improve the real-time PCR analysis for detection of the different variants. METHODS: We genotyped 3395 routine samples using real-time PCR for the -13910C > T-variant. All consecutive samples identified as -13910CC were sequenced using Sanger Sequencing. Using the SDS software we examined various quality value settings to improve on the genetic analysis. RESULTS: Using real-time PCR resulted in 100% successful genotyping of the -13910C > T variant. By using a quality value of 99% and sequencing the undetermined samples we improved the ability of the assay to identify variants other than -13910C > T. This resulted in a reduction of the diagnostic error rate by a factor of 2.4 while increasing the expenses only 3%. CONCLUSIONS: We conclude that using a quality value of 99% in the SDS software significantly improves the diagnostic efficiency of the real-time PCR assay for detecting variants associated to lactase persistence.

Evaluation of p16(INK4a)/Ki-67 dual stain in comparison with an mRNA human papillomavirus test on liquid-based cytology samples with low-grade squamous intraepithelial lesion.

BACKGROUND: The objective of the current study was to investigate the clinical performance of detecting high-grade lesions with the CINtec PLUS p16(INK4a)/Ki-67 dual stain and the APTIMA human papillomavirus (HPV) Assay in a cohort of women with low-grade squamous intraepithelial lesion (LSIL) cytology. The authors also assessed the reproducibility of the evaluation of immunocytochemical staining. METHODS: The 2 tests were performed on liquid-based residual material from 469 women with LSILs. The samples had at least 5 years of follow-up and the gold standard used was high-grade cervical intraepithelial neoplasia (CIN2+/CIN3+) proven on histology. RESULTS: Approximately 69% of all the women included in the study had a positive test for HPV mRNA and 56% was positive for the dual stain. The 2 tests demonstrated high sensitivities. When examining the specificities, the APTIMA HPV Assay performed with significantly lower values than the CINtec PLUS test. For patients with CIN2+, the APTIMA HPV Assay had a specificity of 36.1% versus 51.3% for the CINtec PLUS test, and for women with CIN3+, the specificity was 33.8% versus 48.2%, respectively. The difference was even more pronounced when analyzing women aged < 30 years separately. The kappa values between the 3 observers in scoring the dual stain ranged from 0.43 to 0.49 and improved in a second evaluation round to values ranging from 0.50 to 0.66. CONCLUSIONS: The CINtec PLUS p16(INK4a)/Ki-67 dual-staining test in LSIL cytology samples demonstrated high sensitivity that was similar to that of the APTIMA HPV Assay in the detection of underlying high-grade disease but with enhanced specificity, especially among women aged < 30 years. The kappa value for the evaluation of the CINtec PLUS dual-staining test was moderate but could be improved through training.

Clinical performance of a human papillomavirus messenger RNA test (Aptima HPV Assay) on residual material from archived 3-year-old PreservCyt samples with low-grade squamous intraepithelial lesion.

CONTEXT: Human papillomavirus (HPV) testing is widely used in the triage of women with a borderline smear result but the efficiency of testing women with low-grade squamous intraepithelial lesion (LSIL) is less clear, mainly because of lack of specificity. New HPV tests are emerging, which detect E6/E7messenger RNA (mRNA), and preliminary data suggest that they might have a higher specificity. However, mRNA is less stable than DNA, thus posing a challenge to the preservation abilities of the cell-collecting medium. OBJECTIVE: To evaluate the clinical performance of an HPV mRNA assay on 3-year-old archived liquid-based samples, all with a diagnosis of LSIL. DESIGN: The residual material from old archived PreservCyt samples from 442 women were tested with the Aptima HPV Assay, which detects E6/E7 mRNA from 14 high-risk HPV types. The samples had been stored at room temperature without any further handling. RESULTS: Follow-up was available for 405 women, 67 of whom had histologic confirmed cervical intraepithelial neoplasia (CIN) 2+ and 31 with CIN 3+. The sensitivity and specificity for the mRNA assay was 92.5% and 38.2%, respectively, for detecting CIN 2+, and 93.9% and 35.5%, respectively, for detecting CIN 3+. When evaluating separately the performance of the test for women younger than 30 years and for women 30 years or older, the sensitivity was found to be similar in the 2 groups, but the specificity was significantly lower for the younger women. CONCLUSION: Messenger RNA is well preserved in old archived PreservCyt samples. Triaging women with LSIL, using the Aptima HPV Assay, seems to be effective with a good sensitivity and a good specificity, especially for women 30 years or older.

Epidermal growth factor (EGF) A61G polymorphism and EGF gene expression in normal colon tissue from patients with colorectal cancer.

INTRODUCTION: EGF/EGFR interactions are important mechanisms behind colorectal tumour development and growth. Recently a single nucleotide polymorphism in the EGF gene has been identified (EGF A61G). It may be a potential predictor for survival of patients receiving EGFR-inhibitor cetuximab treatment, but the clinical importance and the functional influence on EGF gene expression levels in colorectal cancer (CRC) patients have not yet been further assessed. The aim of the present study was to investigate the relationship between EGF A61G genotype and EGF gene expression levels in colorectal adenocarcinomas and normal colon tissue. MATERIAL AND METHODS: Eighty-one CRC patients were included in the study. Tissue samples from normal colon, adenocacinomas and corresponding blood samples were analysed by real-time PCR for EGF gene expression and EGF A61G genotype, respectively. RESULTS: Thirty-three percent were AA, 48% and 19% A/G and G/G respectively. We found a significantly lower median age in the A/A group compared to the G/G group, suggesting a later time of diagnosis in the G/G patients. There was a significant difference between the median EGF gene expression among the three genotypes in normal colon (p < 0.001) but not in adenocarcinomas. Furthermore, the median EGF gene expression was lower in CRC tissue than in normal colon samples, (0.13 (range 0.01-6.4) vs. 0.76, (range 0.013-5.55)). CONCLUSION: We suggest that EGF A61G genotype has a functional influence on EGF gene expression in normal colon in CRC patients. The clinical implications warrant further investigations in prospective trials.

Insulin induces a transcriptional activation of epiregulin, HB-EGF and amphiregulin, by a PI3K-dependent mechanism: identification of a specific insulin-responsive promoter element.

Previously we have shown that insulin-stimulation of RT4 bladder cancer cells leads to increased proliferation, which require HER1 activation, and is accompanied by increased mRNA expression of the EGF-ligands heparin-binding EGF-like growth factor (HB-EGF), amphiregulin (AR), and epiregulin (EPI) [D. Ornskov, E. Nexo, B.S. Sorensen, Insulin-induced proliferation of bladder cancer cells is mediated through activation of the epidermal growth factor system, FEBS J. 273 (2006) 5479-5489]. In the present paper, we have investigated the molecular mechanism leading to this insulin-induced expression. We monitored the decay of mRNA after inhibiting transcription with Actinomycin D and demonstrated that the insulin-mediated increase was not caused by enhanced mRNA stability. In untreated cells, HB-EGF mRNA was the least stable, whereas AR and EPI mRNA decayed with slower kinetics. However, promoter analysis of HB-EGF and EPI demonstrated that insulin stimulated transcription. Studies on the EPI promoter identified the insulin-responsive element to be located in the region -564 to -365bp. This region contains potential binding sites for the transcription factors SP1, AP1, and NF-kappaB. Interestingly, all three transcription factors can be activated by PI3K. We demonstrate that the insulin-induced expression of HB-EGF, AR, and EPI mRNA is completely prevented by the specific PI3K inhibitor Wortmannin, suggesting an involvement of the PI3K.

Insulin-induced proliferation of bladder cancer cells is mediated through activation of the epidermal growth factor system.

The mechanism behind the growth-promoting effect of insulin is a subject of debate. Employing RT4 bladder cancer cells, we examined the cross-talk between insulin and the epidermal growth factor system. We found that insulin induced a time- and dose-dependent (25-1000 nmol.L(-1) insulin) increase in mRNA expression of three ligands from the epidermal growth factor system. Times for peak increase and fold increase after incubation with 250 nmol.L(-1) insulin were as follows: heparin-binding epidermal growth factor-like growth factor, 0.5 h, 1.4-fold, P < 0.05; epiregulin, 3 h, 14-fold, P < 0.0001; and amphiregulin, 3 h, 12-fold, P < 0.001. Induction of heparin-binding epidermal growth factor-like growth factor and amphiregulin was verified at the protein level. We demonstrate that incubation of RT4 bladder cancer cells for 24 h with 250 nmol.L(-1) insulin increases proliferation by 43% (P < 0.0001) as compared to untreated cells. At the same time, phosphorylation and thereby activation of the epidermal growth factor receptor (HER1) was observed. Both phosphorylation and insulin-induced proliferation were almost completely inhibited by the HER1 inhibitor Iressa (P < 0.0001). This shows that insulin leads to activation of HER1, and that HER1 plays an essential role in mediating the growth-promoting effect of insulin. Iressa inhibited not only the activation of HER1 caused by insulin but also the insulin-induced increase in the three ligands (heparin-binding epidermal growth factor-like growth factor, epiregulin and amphiregulin). As heparin-binding epidermal growth factor-like growth factor was induced before epiregulin and amphiregulin upon insulin stimulation, we speculated that the insulin-induced heparin-binding epidermal growth factor-like growth factor initiated the activation of HER1, and that this in turn led to increased expression of epiregulin and amphiregulin and thereby to continued activation of HER1. Earlier reports have shown that insulin-like growth factor receptor can activate HER1 via its ligand heparin-binding epidermal growth factor-like growth factor. In accord with this, we found that treatment of RT4 cells with recombinant heparin-binding epidermal growth factor-like growth factor mimicked the effect of insulin, with induction of mRNA for the three ligands. However, the insulin-induced increase in mRNA expression of amphiregulin and epiregulin could not be prevented by the heparin-binding epidermal growth factor-like growth factor inhibitor CRM197, demonstrating that heparin-binding epidermal growth factor-like growth factor is not essential for the insulin-induced increase in the expression of these ligands. In conclusion, we show that insulin-induced growth in RT4 cells requires activated HER1. Furthermore, activation of HER1 is required for the insulin-induced increase in expression of the HER1 ligands heparin-binding epidermal growth factor-like growth factor, amphiregulin and epiregulin.

The chemotherapeutic agent VP16 increases the stability of HB-EGF mRNA by a mechanism involving the 3'-UTR.

VP16 is a chemotherapeutic agent that introduces DNA damage. We demonstrate that cellular stress induced by VP16 in the human cervix cancer cell line HeLa increases the HB-EGF (heparin binding epidermal growth factor like growth factor) mRNA level dose dependently. Maximal induction (10-fold) was observed at 20-40 microM VP16. Increased HB-EGF peptide levels accompanied the increase in HB-EGF mRNA. We investigated the molecular mechanism involved in HB-EGF mRNA induction by VP16. Transcription was only slightly increased (60%) as determined by real-time PCR quantification of transcription from a reporter plasmid containing the HB-EGF promoter in front of the luciferase gene. In contrast, HB-EGF mRNA stability was increased significantly by VP16 as demonstrated by monitoring HB-EGF mRNA decay in cells treated with the transcriptional inhibitor actinomycin D. The 3'-UTR (3'-untranslated region) of HB-EGF was inserted at the 3'-end of LacZ mRNA. VP16 treatment of the cells caused a 5-fold increase in this chimeric mRNA, as compared to LacZ without this 3'-UTR. A 186 nucleotide region of HB-EGF contains five of the six AUUUA sequences found in the 1454 nucleotide 3'-UTR of HB-EGF and we demonstrate that this region caused an approximately 3-fold induction of LacZ mRNA when inserted at the 3'-end, as compared to LacZ without any insertion at the 3'-end, demonstrating that a significant proportion of the effect resides in this region. Induction of HB-EGF by VP16 has important implications as HB-EGF has been reported to prevent cell death, which might lower the efficacy of chemotherapy. We demonstrate that mRNA stability and in particular the HB-EGF 3'-UTR is involved in the HB-EGF mRNA induction.