title: Characterization of choline kinase in human endothelial cells.
abstract: High choline kinase-α (Chk-α) expression is frequently observed in cancer cells, making it a novel target for pharmacological and molecular inhibition. As inhibiting agents are delivered systemically, it is important to determine Chk-α expression levels in endothelial cells that line both normal and tumor vasculature, and the effect of Chk-α downregulation on these cells. Here, we characterized Chk-α expression and the effect of its downregulation in human umbilical vein endothelial cells (HUVECs) relative to MDA-MB-231 human breast cancer cells. We used small interfering RNA (siRNA) to downregulate Chk-α expression. Basal mRNA levels of Chk-α were approximately three-fold lower in HUVECs relative to MDA-MB-231 breast cancer cells. Consistent with the differences in Chk-α protein levels, phosphocholine levels were approximately 10-fold lower in HUVECs relative to MDA-MB-231 cells. Transient transfection with siRNA-Chk resulted in comparable levels of mRNA and protein in MDA-MB-231 breast cancer cells and HUVECs. However, there was a significant reduction in proliferation in MDA-MB-231 cells, but not in HUVECs. No significant difference in CD31 immunostaining was observed in tumor sections obtained from mice injected with control luciferase-short hairpin (sh)RNA or Chk-shRNA lentivirus. These data suggest that systemically delivered agents that downregulate Chk-α in tumors will not affect endothelial cell proliferation during delivery, and further support the development of Chk-α downregulation as a cancer-specific treatment.
authors.affiliation: JHU ICMIC Program, Division of Cancer Imaging Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, School of Medicine, Baltimore, MD, USA.
authors.forename: Noriko
authors.initials: N
authors.lastname: Mori
authors.forename: Mayur
authors.initials: M
authors.lastname: Gadiya
authors.forename: Flonné
authors.initials: F
authors.lastname: Wildes
authors.forename: Balaji
authors.initials: B
authors.lastname: Krishnamachary
authors.forename: Kristine
authors.initials: K
authors.lastname: Glunde
authors.forename: Zaver M
authors.initials: ZM
authors.lastname: Bhujwalla
mesh_terms: D000818:Animals; D002457:Cell Extracts; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D002797:Choline Kinase / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation; D015971:Gene Expression Regulation, Enzymologic; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection
chemical_list: D002457:Cell Extracts; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D002797:Choline Kinase
keywords: MRS; angiogenesis; breast cancer; choline kinase; endothelial cells; phosphocholine; proliferation