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Abstract #1545

siRNA-Mediated Silencing of the Glycerophosphocholine Phosphodiesterase GDPD5 in Breast Cancer Cells

Maria Dung Cao1, Lu Jiang2, Tiffany R. Greenwood2, Balaji Krishnamachary2, Zaver M. Bhujwalla2, Ingrid S. Gribbestad1, Kristine Glunde2

1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

We previously demonstrated that the glycerophosphocholine phosphodiesterase (GPC-PDE) encoded by GDPD5 is partially responsible for the relatively low glycerophosphocholine (GPC) levels in human breast tumor samples, and that it is associated with cancer malignancy. Here we transiently silenced GDPD5 in human breast cancer cells using siRNA. Magnetic resonance spectroscopy revealed increased GPC levels following GDPD5 silencing, suggesting that GDPD5 catalyzes the degradation of GPC in human breast cancer cells. Total choline and phosphocholine levels increased in highly malignant MDA-MB-231 cells, but not in weakly malignant MCF-7 cells upon GDPD5 silencing, indicating different roles of GDPD5 in these two cell lines.