Sterol Regulatory Element-Binding Protein 1 Transcription Factor in Regulation of Lipid Production in Cancer Cells

Julia Steger

Authors:  Julia Steger

Faculty Mentor:  Liao Daiqing

College:  College of Medicine


Understanding cancer biology mechanisms is vital to discover novel treatments to improve patient outcome. Cancer cells utilize de novo lipogenesis to satiate their bioenergetic demands juxtaposed to normal cells relying on extracellular supplies of lipids. Sterol Regulatory Element-Binding Protein 1 (SREBP-1) is a transcription factor in controlling lipid metabolism that is vital in tumor lipogenesis. Certain cell growth conditions, such as the presence of an external lipid supply, has been shown to reduce SREBP-1 nuclear expression. In contrast, SREBP-1 nuclear expression is upregulated in medium with no external lipids. Whereas SREBP-1 upregulation in breast cancer has been demonstrated, precisely how its activity is regulated under various metabolic conditions remains incompletely understood. We evaluated the impact of cell growth medium on SREBP-1 intracellular localization in order to understand the mechanistic link between de novo lipogenesis and cell proliferation. We used a variety of immunofluorescence assays to visualize SREBP-1 intracellular localization under different cell culture conditions. We found decreased SREBP-1 nuclear localization in the presence of an external supply of lipids in the cell culture medium, while the nuclear level of SREBP-1 was markedly increased in medium lacking serum. Future studies will examine whether specific lipids modulate SREBP-1 expression and intracellular localization.

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5 Responses
  1. Mary Jo Koroly

    Very nice poster and presentation, Julia. Is it possible to grow these cells in a media in which lipid content is defined?

    1. Julia Steger

      Hi Mary. Thank you! You could grow these cells in a media where lipid content is defined like was done in this experiment with 1% BCS vs 10% BCS. Once the cells do not have adequate nutrient supply, they will up-regulate the production of SREBP-1a and you will see higher nuclear localization in those cells.