HUMAN PAPILLOMAVIRUS GENE EXPRESSION IN CERVICAL CANCER

Project: Research project

Project Details

Description

This project will test the hypothesis that mapping the viral RNA
and characterizing the early viral proteins of human
papillomavirus (HPV) will improve our understanding of how these
viruses alter the normal keratinocyte and how this may relate to
carcinogenesis of the cervix. HPV gene expression will be studied
in fresh tumor and wart tissues, in tumor cell lines, and in vector
systems designed to express viral genes after transfection into
cultured cells. It is proposed that:

1. HPV messenger RNA will be mapped and quantitated in benign
warts and invasive tumors. Comparisons will be made between
different tumors and between benign and malignant lesions so as
to obtain insight into which genes may be important in
carcinogenesis and to try to explain why some viral types such as
HPV 16 and 18 are commonly associated with malignancy while
other types such as HPV6 and 11 are almost exclusively associated
with benign lesions.

2. The early proteins of HPV will be identified and characterized
with special emphasis on the E6 and E7 proteins, the major viral
proteins in cervical cancer. Antibodies will be made against the
E6, E7, E2, and E4 proteins of various types of HPV. The major
messenger RNA in benign genital lesions appears to code for E4
and therefore E4 may be present in large enough amounts to be
detectable by immunoperoxidase methods, and thus may be useful
for clinical diagnosis.

3. When HPV DNA is introduced into cultured cells it is not
replicated in a stable fashion, nor are the viral genes expressed in
detectable amounts. In order to overcome this block in expression
two approaches will be taken. First, vectors will be made
whereby the early viral genes will be placed under the control of
exogenous strong or inducible promoters. Expression of viral
proteins and RNA will be looked for in transient transfection
conditions and after permanent transformation of cells. HPV
DNA has been shown to immortalize primary keratinocytes, a
phenotypic change that may relate to carcinogenesis. These
vectors will be used to develop a system for analysing what genes
are important in the immortalizion process. The second approach
will attempt to enhance viral gene expression by cotransfecting
the HPV genome along with a vector expressing the viral E2 gene
behind a strong exogenous promoter. E2 is a transcriptional
trans-activator and supplying large amounts in trans may
overcome the block in vitro viral gene expression and may even
allow viral DNA replication.
StatusFinished
Effective start/end date1/1/901/1/90

Funding

  • National Cancer Institute

ASJC

  • Genetics
  • Molecular Biology
  • Cancer Research
  • Virology
  • Histology

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