Immunostaining of the cultured cells was carried out as described previously (Yamamizu et al., 2012a, Yamamizu et al., 2010). In brief, 4% paraformaldehyde-fixed cells were blocked by 1% skim milk (BD Biosciences) and incubated overnight with primary antibodies at 4°C. For immunofluorescence staining, anti-mouse, rat, rabbit, or goat immunoglobulin G (IgG) antibodies conjugated with Alexa 488 or Alexa 546 (Life Technologies) were used as secondary antibodies. Nuclei were visualized with DAPI (Life Technologies). Stained cells were photographed with the inverted fluorescence microscope BZ-9000 (Keyence) or Eclipse TE2000-U (Nikon) and a digital camera system (AxioCam HRc, Carl Zeiss) with the use of AxioVision 4.7.1 Software (Carl Zeiss). The following primary antibodies were used for immunostaining: anti-mouse CD31 antibody (BBA7; R&D; 1:1,000), anti-rabbit CD31 antibody (ab134168; Abcam; 1:1,000), anti-VE-CADHERIN antibody conjugated with phycoerythrin (PE) (12-1449-80; BD Biosciences; 1:200), anti-αSMA antibody (A2547; Sigma-Aldrich; 1:1,000), anti-SM22α antibody (ab10135; Abcam; 1:500), anti-CALPONIN (ab46794; Abcam; 1:500), anti-NG2 (14-6504-80; eBioscience; 1:500), anti-NESTIN antibody (MAB5326; Millipore; 1:500), anti-mouse TUJ1 antibody (MAB1637; Millipore; 1:1,000), anti-rabbit TUJ1 antibody (845501; Covance; 1:1,000), anti-GFAP antibody (IS524; Dako; 1:100), anti-BCRP antibody (MAB995; R&D;
