Use of Cytokines to Prevent Breast Cancer Growth and Progression
Abstract
Interferon-alpha/beta (IFN-alpha/beta) and prolactin (PRL) are natural ligands relevant to breast cancer progression: IFN-alpha/beta inhibits proliferation while PRL stimulates growth. The IFN alpha/beta antiproliferative action is mediated by STAT I in a transcriptional holocomplex with STAT2 and ISGF3 gamma -p48). #1We investigated a negative regulator of -p48 function, designated "TKO". Proteins in a cytosol fraction enriched for "TKO" were resolved by 2D PAGE. The p48-binding "TKO" -22 kDa) was identified by depletion analyses. Microsequencing showed homology to alkylhydroperoxidase reductase C/thiol-specific antioxidants (AhpC / TSA). This superfamily includes human peroxiredoxins (Prx). Amino acid sequences in TKO peptide fragments most closely matched the Prx gene PagA . Primers were designed to amplify a unique portion of PagA for measurements of expression, and multiple breast cancer cell lines proved positive by RT-PCR. Polyclonal antibodies to synthetic oligopeptides also showed Prx expression. The full-coding sequence of PagA was tagged and cloned for transfer into insect cells with a baculovims vector, and insect cell-expressed PagA was isolated for antibody production. #2 STAT 1 serves as a transcription factor both for PRL and IFN-alpha/beta. Tests for signal competition and potentially antagonistic "cross-talk" of PRL and IFN-alpha/beta during STAT1 tyrosine phosphorylation nevertheless proved consistently negative in either well or poorly differentiated breast cancer cells. IFN-gamma pretreatment augmented IFN-alpha/beta antiproliferative activity, presumably due to an enhancement of -p48 expression. Unexpectedly, it also enhanced STAT5 and STAT3 DNA-binding.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1999
- Accession Number
- ADA382941
Entities
People
- Philip M. Grimley
Organizations
- Henry M. Jackson Foundation for the Advancement of Military Medicine