Deregulation of Tropomyosin Expression in Human Breast Cancer.
Abstract
Human breast cancer cell lines and invasive tumors frequently have reduced tropomyosin (TM) expression. We wish to identify the normal function of the TM isoforms expressed in breast epithelial cells and determine if altered TM expression has prognostic value in human breast cancer. The first step is to determine which TM isoforms most frequently exhibit altered expression in human breast cancers, compared to normal, mortal human mammary epithelial cells (HMEC). Using Northern and Western blot analysis to characterize TM expression in an in vitro cell culture model of human breast cancer we determined that TM1 RNA is reduced in the breast cancer cell lines SKBR3, MCF7, T47D and MDA-MB-435 while in MDA-MB-231 cells, TM1 RNA is increased, relative to normal, mortal HMEC, correlating with reduced TMl protein. TM4 RNA is increased in the benign, immortalized breast cell lines HBLi00, 184A1N4 and in the cancer cell lines 184A1N4T11 and SKBR3, but shows no significant differences in abundance in MDA-MB-231, MCF7, T47D and MDA-MB-435 breast cancer cells. TM4 protein is reduced in the latter four cell lines. Immunohistochemistry performed on human breast tumor samples reveals decreased HMW TM (TM1) expression in sixty per cent of infiltrating ductal carcinomas examined thus far.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1998
- Accession Number
- ADA353884
Entities
People
- Lawrence M. Mielnicki
Organizations
- Roswell Park Comprehensive Cancer Center