Abstract 3241: Analysis of transcription factor activation by the embryonic microenvironment in metastatic breast cancer cells

Abstract

Abstract Introduction: The embryonic microenvironment is an important source of signals that program multipotent cells to adopt a particular fate. Numerous studies have shown that components of the embryonic stem cell microenvironment can induce a reversion of cancer cell phenotype from a more aggressive to less aggressive state through mechanisms that are largely unknown. We have examined the phenotypic transformation associated with the culture of metastatic breast cancer cells in mouse embryonic stem cell conditioned media and have implemented a novel cell array technology to characterize the signaling pathways associated with this transformation. Methods: We used phase contrast microscopy to determine the time course of structure formation in MDA-MB-231 cells cultured in 3D with control or conditioned mouse embryonic stem cell media. Cell proliferation of study cells stably expressing Gaussia Luciferase was quantified by measuring Gluc production over time. Cell migration was measured for treated and untreated cells using a transwell migration assay. A live cell array was implemented to quantify changes in activity of 19 cancer-related transcription factors over a period of 8 days. Results: MDA-MB-231 cells cultured in stem cell conditioned media showed decreased area covered by spindle-like projections over a period of 10 days. Study cells cultured in stem cell conditioned media, but not in control media or mouse embryonic fibroblast conditioned media, had decreased proliferation over time. Cells cultured in stem cell conditioned media had decreased cell migration relative to cells cultured with regular media. Using a cell array to report on TF activity, cells cultured in conditioned stem cell media, when compared to control media, had varied activity in 7 of the 19 constructs investigated, including metastasis-related factors SP1 and GATA1. Conclusion: Our findings support the normalizing influence provided by the stem cell microenvironment through decreased MDA-MB-231 spindle-like projections, cell proliferation, and cell migration. Of the 19 transcription factor reporter constructs tested using the novel live cell array, GATA1 and SP1 emerged as 2 of the transcription factors impacted by the embryonic microenvironment. These factors may reflect potential paracrine signaling pathways stimulated by the microenvironment that can influence transformation and may be targets for therapeutic intervention. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3241. doi:1538-7445.AM2012-3241