Abstract 1801: ERK-mediated regulation of NFAT3 enhances CXCR4 expression in HeyA8 ovarian cell line.

Abstract The G-protein coupled chemokine (C-X-C motif) receptor CXCR4 is linked to cancer, HIV, and WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome. While CXCR4 is widely studied and characterized extensively to be over-expressed in multiple human tumor tissues, we have seen poor surface CXCR4 expression in many solid tumor cell lines in vitro. To better understand how CXCR4 is regulated, cells grown under 3-D spheroid conditions were compared to normal adherent culturing conditions. When cultured as 3D spheroids, HeyA8 cells showed a dramatic increase in surface CXCR4 protein levels as well as mRNA transcripts. Furthermore, HeyA8 3D spheroids showed a decrease in pERK levels when compared to adherent cells. Using an inhibitor of the MEK-ERK pathway, the treatment of adherent HeyA8 cells with U0126 resulted in a significant increase in surface CXCR4 expression similar to 3D spheroids. Additional investigation using PCR array showed a wide range of transcription factors being up-regulated but notably a > 20 fold increase in NFAT3 transcription factor. Using a calcineurin inhibitor, cyclosporin A diminished the U0126 treated up-regulation of CXCR4 surface expression. Finally, Chromatin Immunoprecipitation analysis showed direct binding of NFAT3 on the CXCR4 promoter to increase CXCR4 expression in HeyA8 ovarian cell line. Taken together, our results suggest that phospho-ERK levels regulate CXCR4 expression through the NFAT3 signaling pathway. Citation Format: Keven Huang, Christine Kiefer, Adeela Kamal. ERK-mediated regulation of NFAT3 enhances CXCR4 expression in HeyA8 ovarian cell line. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1801. doi:10.1158/1538-7445.AM2013-1801 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.