Document Type

Theses, Ph.D

Rights

This item is available under a Creative Commons License for non-commercial use only

Disciplines

1.6 BIOLOGICAL SCIENCES

Publication Details

Thesis successfully submitted to the Dublin Institute of Technology for the award of Doctor of Philosophy, January, 2008.

Abstract

Cervical cancer is second only to breast cancer as the most common cancer among women worldwide and is caused by Human Papillomavirus (HPV). The aim of this study was to evaluate the role of RNA-binding proteins in the expression of HPV in cervical cells and clinical samples. Firstly, an audit was performed on cervical biopsy samples taken by laser loop excision over 5 years in the National Maternity Hospital, Holles Street, Dublin, Ireland. The presence of HPV and HPV-16 was evaluated on fifty of these samples and the distribution of multiple RNA-binding proteins, including SR proteins and hnRNPs, was evaluated and related to differentiations (cytokeratins, syndecan) and proliferation-associated (PCNA, p161INK4a) biomarkers. The samples consisted of histologically normal cervical epithelium, HPV-induced low-grade and high-grade pre-malignant lesions and cervical cancers. Low expression of these proteins was detected in basal epithelial cells of normal cervix, with increased expression in intermediate layers, and a lack of expression in the upper superficial layers. Expression of all RNA-binding proteins increased in neoplastic lesions and highest expression was demonstrated in intermediate layers, and a lack of expression in the upper superficial layer. Expression of all RNA-binding proteins increased in neoplastic lesions and highest expression was demonstrated in cervical cancers. The expression profile of the RNA-binding proteins was similar to PCNA expression in normal and lesional cervical epithelia, but was not associated with HPV-16 status, p16INK4a or differentiation markers. The effect of a number of these proteins on transcription of the late HPV genes was evaluated in modified HeLa cell lines (pBEL and pBELM) by transfection studies, with effects evaluated using real-time PCR and Northern blot analyses. It was determined that adenoviral E4orf4, splicing proteins SRp30c and PTB as well as HPV-16 E2 can induce the expression of the late HPV genes and these were shown to alter the ratio of expression of HPV L1 mRNAs, demonstrating that these proteins may play a role in the differential expression of proteins during the HPV life-cycle.

DOI

10.21427/D7259Z

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