Cell Labeling with Fluorescent Dyes

All chemicals used in this study were purchased from Sigma-Aldrich (St. Louis, USA) and used as received. Cell culture plates, FBS, penicillin, streptomycin, sodium bicarbonate, cell culture medium, and phosphate-buffered saline (PBS) were purchased from GIBCO BRL (Frederick, MD). Lipofectamine 2000 transfection reagent and the Vibrant Multicolor Cell-Labeling Kit containing DiOC18 (3) (3,3′-dioctadecyloxacarbocyanine perchlorate) (DiO), 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindodicarbocyanine, and 4-chlorobenzenesulfonate salt (DiD) solutions, protein gels, and buffers for gel electrophoresis and immunoblot analysis were purchased from Invitrogen (Carlsbad, CA). Cy5-labeled AntimiR-21 RNA-oligo was synthesized from Protein and Nucleic acid facility at Stanford (PAN, Stanford).^{19 (link)}