Characterization of SIRPs in Prostate Cancer Cells
Abstract
Signal regulatory proteins (SIRPs include SIRP(3l, which activates cells, and SIRP alpha 1, which inhibits the cellular response to several growth factors, and which regulates cell adhesion and spreading. We demonstrated by PCR that 3 of 3 prostate cancer cell lines (PC-3, DU-145 and LNCaP) express transcripts for SIRPs. Under this contract, we generated a monoclonal antibody that recognizes both SIRP beta and SIRP alpha 1, thereby confirming the expression of SIRPs on PC-3 cells and, to a lesser extent on DU-145 cells. The receptor could not be detected on LNCaP cells. We have since shown by PCR, Western blotting, and by surface staining that PC-3 and DU-145 cells express SIRP alpha 1 but not SIRP beta. We found that they also express the tyrosine phosphatase, SHP-2, and that SHP-2 binds to SIRP alpha 1 when it is phosphorylated, demonstrating that this pathway for the function of SIRP alpha 1 is intact. We have created constructs of epitope-tagged SIRP alpha 1, either intact or with mutations that would alter SHP-2 binding, in order to study its function in PC-3 cells. We have also worked in particular on the characterization of the SIRP alpha 1 protein in prostate cancer cells. Is there more than one form, due either to alternate splicing or to post-translational modification? These studies have proved challenging, but we expect to complete them, along with all of the objectives of the contract, over the coming year (no-cost extension).
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2004
- Accession Number
- ADA427819
Entities
People
- William E. Seaman
Organizations
- Northern California Institute for Research and Education