CDNA Microarray Based Comparative Gene Expression Analysis of Primary Breast Tumors Versus In Vitro Transformed Neoplastic Breast Epithelium.

摘要

We have transfected the 184B5 immortalized, non-transformed human mammary epithelial cell line with the oncogenic mutant ras gene and with empty vector. We have isolated the following stable transfecants: (1) cells overexpressing the mutant ras oncogene (2) cells overexpressing the normal, non- mutant form of ras (3) cells transfected with the empty vector. The first group of clones is being sorted by their ability to form tumors. We are currently performing cDNA microarray analysis quantifying the expression level of about 15,000 genes in these cell lines. We have also performed cDNA micorarray analysis on several established breast cancer derived cell lines. The comparative analysis will reveal the gene expression similarity between the cell lines that were transformed by the ras oncogene. This will determine whether gene expression patterns could be used to infer that certain breast tumor samples were originated, at least partially, by the ras oncogene. We are also comparing the gene expression patterns derived from in vitro transformed cells to the gene expression profile of primary breast tumors and established breast cancer cell lines. This will help to assess the ratio of gene expression changes in primary breast tumors that could be attributed to the presence of the above listed oncogenic changes. If this ratio is low, then the potential role of other oncogenic factors in the development of breast cancer will be substantiated. The opposite result will support the definitive role of these already known oncogenes in sporadic breast cancer. We will also compare the tumor forming and the non-malignant clones that both overexpress the ras oncogenes and determine which ras inducible genes are relevant for tumor formation.