Role of DNA Methylation in Altering Gene Expression During the Early Stages of Human Breast Cancer Progression in the MCF10AT Xenograft Model

摘要

We hypothesize that a simple, interpretable pattern can be derived by following changes in breast cells from a single individual as they undergo progression from normal appearing ductular forms to the appearance of carcinoma- in-situ and invasive cancer. We proposed to (1) Collect enough microdissected tissue representative of each of the morphologically different stages of early breast cancer progression in the MCF10AT model to obtain RNA for microarray analysis of gene expression and PCR-amplification of DNA for analysis of global and gene specific CpG island methylation. (2) Compare the methylation patterns of candidate genes in these tissues with those of MCF10A, MCF10AT and MCF10DCIS . com. cells in culture. (3) Prepare a CpG island methylation profile and a gene expression profile for each of the tissue types and cell lines. This year we completed examination of DNA methylation in 15 CpG islands in genes whose silencing by methylation has been linked to cancer development using MCF-7 and MCF10A cells and 6 cell lines in the MCF10AT model. The results of this analysis have been coupled with gene expression data and validate our methods. We have also collected sufficient tumor tissue from xenografts to carry out analysis of methylation status in xenografts during progression.