Polycomb Proteins and Breast Epithelial Cell Transformation
Abstract
Polycomb group (PcG) proteins, although initially thought to play an exclusive role in development appears to regulate tumorigenesis via regulation of cell proliferation and senescence. Recently it was reported that Bmi-1, a polycomb oncoprotein is overexpressed in breast cancer cells and invasive breast tumors. Bmi-1 overexpression immortalizes breast epithelial cells. Importantly, EZH2, a different polycomb protein was reported to be a marker of aggressive breast cancer and facilitator of neoplastic transformation of immortalized breast epithelial cells. Like any other cancer, breast cancer is a mutlistep process; bypass of cellular senescence and cellular immortalization are considered early steps in the tumorigenesis. Here, we examined the possibility that two different polycomb proteins such as Bmi-1 and EZH2 can together fully transform normal breast epithelial cells. Normal breast epithelial cells (BECs) expressing Bmi-1, CBX-7 and EZH2 alone or in combination were genearated. Cells expressing different combinations of these polycomb proteins were tested for oncogenic properties. Our results indicate that polycomb combinations does not fully transform BECs. However, coexpression of activated H-Ras in Bmi-1 expressing breast cells generated fully transformed phenotype.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2005
- Accession Number
- ADA447514
Entities
People
- Goberdhan P. Dimri