Identification of Structural Domains of ESX Required for Breast Cell Transformation
Abstract
ESX encodes an Ets family transcription factor gene that is potentially important in breast cancer because the ESX genomic region (chromosome 1q32.l) is amplified in 50% of early breast cancers and ESX mRNA is over-expressed in human breast ductal carcinoma in situ (DCIS) . However, the precise molecular mechanism by which ESX mediates breast cell transformation remains unknown. We have previously shown that the non-transformed MCF-l2A cell line fails to express ESX, while the transformed T47D breast cancer cell line does express ESX. When we enforce ESX expression in MCF-l2A cells, they display a transformed phenotype, whereas abrogation of endogenous ESX expression in T47D cells results in a marked reduction of T47D colony formation. We generated a GFP-ESX fusion to determine its subcellular localization, via confocal microscopy, in NCF-l2A cells stably expressing GFP- ESX. To our surprise, we found that GFP-ESX is initially expressed in the nucleus and then stably appears in the peri-nuclear cytoplasmic region. Since these GFP-ESX stable cell lines also display the transformed phenotype, the question arises as to how a putative transcription factor residing in the cytoplasm mediates cellular transformation? Supporting this notion is that immuno-histochemical analyis of primary human breast cancer specimens and T47D cells, also show that ESX localization is primarily cytoplasmic. These data indicate that ESX functions primarily via cytoplasmic mechanisms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2002
- Accession Number
- ADA407404
Entities
People
- Arthur Gutierrez-hartmann
Organizations
- University of Colorado Health