G0S2: Establishing a Role in Breast Epithelial Differentiation and Cancer

G0/G1 switch gene 2 (G0S2) is a direct retinoic acid target gene widely expressed in diverse organs and implicated in cancer based on frequent methylation-mediated silencing in diverse solid tumors. We have previously shown G0S2 to be a novel breast cancer tumor suppressor. In addition, there is some evidence that G0S2 is highly expressed in normal breast epithelial tissue and may become downregulated by immortalization and transformation. We found that G0S2 is highly expressed in the mammary gland ductal branching of mice. Further, G0S2 knockout mice have a lactation defect. However, its not yet clear whether G0S2 is involved in breast cancer initiation and progression. We hypothesize that G0S2 plays a role in normal breast epithelial cell differentiation and that loss of G0S2 may result in aberrant differentiation leading to a more cancer prone state. Our results show that G0S2 expression is increased during lactogenic induced differentiation in immortalized mouse epithelial cells. We have also observed that not all mouse breast cancer cell lines have a decrease in G0S2 expression compared to normal mouse mammary derived cell lines. For future studies, we will further elucidate the role of G0S2 in breast epithelial differentiation and cancer. This will aid in the development of future breast cancer therapies.Ope