Breast cancer is the most common cancer in women in the Western world, and is the leading cause of cancer related deaths in women worldwide. Many of the molecular factors known to be involved in breast cancer ultimately elicit their effects by causing changes in gene expression. A critical control point for regulating gene expression is at the level of mRNA transcription. In order to control the unchecked growth and invasiveness of breast cancer tumors, an understanding of disease-related perturbations in the transcription levels of genes critical to the progression of the disease must be obtained. The transcriptional activators NFATc2 and cJun have each individually been shown to activate transcription of genes that increase breast cancer cell invasiveness. Whether NFATc2 and cJun cooperate to activate transcription in breast cancer cells is not known, although their cooperation in controlling transcriptional programs in other biological systems is well-established. The intracellular localization of NFATc2 is controlled by levels of cytosolic calcium. Several chemical carcinogens are known to increase cytosolic calcium in mammary epithelial cells or breast cancer cells. Whether these chemicals cause NFATc2 to localize to the nucleus is not known. This pilot study will address the hypothesis that NFATc2 and cJun cooperate to activate transcription of genes that promote breast cancer invasiveness in response to environmental carcinogens known to increase cytosolic calcium. The proposal has three highly focused Specific Aims. 1) Determine the effect of environmental carcinogens known to increase cytosolic calcium on NFATc2 nuclear localization through the use of immunofluorescence. 2) Identify genes at which NFATc2 and cJun co-localize using ChIP-seq after treatment of mammary epithelial cells or breast cancer cells with a carcinogen. 3) Determine whether NFATc2 and cJun cooperate to upregulate expression of genes important to cell growth and invasiveness upon treatment with a carcinogen by knocking down the transcriptional activators and determining the effect on mRNA levels of select genes. The proposed research will determine whether NFATc2 and cJun cooperate to activate transcription in response to treating cells with a chemical carcinogen. Although the studies are focused on breast cancer because of the clear evidence that NFATc2 and cJun promote invasiveness of breast cancer cells, the research will also influence studies of other cancer types in which these factors are also thought to work. The results of these pilot studies will be used as a foundation for new lines of research using cell-based and biochemical studies to unravel the mechanisms by which NFATc2 and cJun activate transcription in breast cancer.
Properly controlling gene expression is essential to sustaining life and avoiding many diseases and cancers;mRNA transcription by RNA polymerase II is central to this process. The proposed studies will test a new hypothesis for how two transcriptional activators cooperate to upregulate the expression of genes important to breast cancer cell development in response to an environmental carcinogen. This research will be an important first step in understanding how these two transcription factors work together to promote breast cancer.