2.5. Immunofluorescence Staining

The immunofluorescence staining was conducted as described previously (Li et al., 2013). Briefly, after treated with deguelin for 24 h, an asynchronous population of cancer cells were washed with PBS, and fixed in 4% paraformaldehyde and permeabilized in 0.5% Triton X-100 for 30 min. Fixed cells were incubated with a α-tubulin rabbit antibody (#2144, Cell Signaling Technology, Danvers, MA) overnight at 4 °C followed by incubation with green fluorescent Alexa Fluor 488 dye-labeled anti-mouse IgG (Invitrogen, Grand Island, NY). Nuclei were stained with DAPI. Samples were viewed with a Nikon inverted fluorescence microscope (Melville, NY).