Role of Mammary Prolactin in Carcinogenesis.
Abstract
A cleaved form of prolactin, named 16K PRL, has been reported to act as an angiostatic agent in several vascular beds. We found that rat mammary gland homogenates can proteolytically cleave PRL and generate 16K PRL. We also detected significant amounts of immunoreactive PRL in human breast tissue and determined that breast cancer cells express PRL receptors and have the capacity to internalize and then release exogenous PRL. Our working hypothesis is that mammary cells internalize PRL from the circulation by a receptor mediated mechanism. Inside the cell, PRL is cleaved to yield 16K PRL, which is then released, binds to specific receptors on neighboring endothelial cells and suppress their proliferation. The process of tumorigenesis is associated with disruption in the formation or action of 16K PRL, thereby enabling angiogenesis and tumor expansion. Ongoing experiments will establish the PRL cleavage capability of human breast tissue, will investigate the presence of 16K PRL in normal and tumorous breast tissue, and will test the angiostatic actions of 16K PRL.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1997
- Accession Number
- ADA337867
Entities
People
- Nira Ben-jonathan
Organizations
- University of Cincinnati