Human papillomavirus type 16 (HPV16) induces squamous intraepithelial lesions of the cervical mucosa which may develop into invasive cancer. The expression of viral oncogenes in advanced neoplasias appears increased relative to the proliferating cell layers of low grade lesions raising questions about molecular mechanisms of deregulation of transcription. In a lymph node metastasis of a cervical cancer, we observed full‐length HPV16 plasmids and molecules with a small deletion, which was mapped to the long control region (LCR). Both wild type and shortened LCR were amplified by PCR, cloned into the promoter test plasmid pBLCAT6 and sequenced to identify a 107 bp deletion from position 7794 to 7901 in the short LCR. CAT expression in cervical cancer‐derived HT3, SiHa and CaSki cells appeared 5‐ to 6‐fold increased under the control of the short LCR. This could be traced back to elevated levels of mRNA initiated at the viral oncogene promoter. A slight further increase in CAT expression was noted in the presence of the HPV16 E2 protein which is probably due to the deletion of one E2 binding site and consequent relief from E2 repression. Computer‐assisted sequence analysis and band‐shift experiments with purified YY1 protein and wild type or mutated oligonucleotides identified four binding sites for this cellular transcriptional repressor within the promoter‐proximal segment of the HPV16 LCR, three of which were removed by the deletion. A LCR fragment comprising these YY1 binding sites was cloned in front of the heterologous thymidine kinase gene promoter and suppressed CAT expression 3‐ to 4‐fold.(ABSTRACT TRUNCATED AT 250 WORDS)
Expression of the oncogenes E6 and E7 of human papillomavirus 16 (HPV 16) appears enhanced in pre-malignant and malignant genital tumors. We recently identified a transcriptional silencer upstream of the oncogene promoter P97, comprising 4 binding sites for the cellular YY1 protein. The analysis of the long transcriptional control regions (LCR) of episomal HPV 16 DNAs from primary tumors and lymph-node metastases of 6 patients with cervical cancer revealed deletions and point mutations of YY1 binding sites in 4 cases. To test for the activity of the P97 promoter, the mutated LCRs were cloned in a luciferase reporter gene vector. A point mutation in YY1-recognition site 4, which prevents DNA-protein interaction, did not affect promoter activity, probably due to compensation by the overlapping YY1-binding site 3. However, 5.5- to 6.5-fold increased luciferase expression was obtained under the control of 3 shortened LCRs lacking 2 to 4 YY1-binding sites. A point mutation in YY1-recognition site 2, which was previously shown to stimulate P97 3.5-fold, could be detected in the HPV 16 LCRs from both primary tumor and metastasis, indicating that the mutation is a stable characteristic of HPV 16 DNA associated with the individual cancer. These findings suggest that deletions or mutations of YY1-binding sites play a significant role in over-expression of viral oncogenes and tumor progression.
The gene expression of human papillomavirus (HPV) 33, which can be detected both in benign and malignant genital tumors, was analyzed in a cervical condyloma acuminatum by in situ hybridization using open reading frame-specific RNA probes. Viral mRNA concentrations increased with the degree of differentiation of the keratinocytes. The probes for reading frames E4 and E5 generated the most intense signals. The patterns of the specific viral mRNAs were very similar to those in condylomas induced by HPV 6 or 11, which are only rarely associated with malignancies. This implies that in tumors of the same degree of morphological differentiation the gene expression program of different HPV types is essentially identical. The pattern observed here most likely corresponds to a productive phase of viral infection.
Breast cancer centres - certified in accordance with the criteria of the German Cancer Association and the German Mastology Association - are established throughout Germany. Although the setting up of centres and the subsequent need for certification are associated with a marked increase in costs, initial data show positive effects on quality. Certified centres are cost-effective from the point of view of health economics - they lead to improved quality in processes and results without creating any increase in costs for the funding bodies. However, the organization of the necessary structures, with interdisciplinary treatment, documentation and quality-assurance measures, requires considerable resources. Increasing consolidation of inpatient services is also involved, while shortening of the patients' hospitalization periods is leading to reduced remuneration from the funding bodies. The current cost deficits, which have resulted from the increased resources required, need to be recouped through additional charges. It will only be possible to maintain the high quality achieved if additional charges become available to cover the centres' added costs. Good data are increasingly becoming available as a basis for negotiations on charges - e.g., with regard to the quality of results and the National Cancer Plan - as well as clear support from patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.