Fig. 1.

Identification of a small ALDH1A1⁺ population in bladder cancer cell lines. A. FACS analysis of cancer cells using the Aldefluor assay. The brightly fluorescent ALDH1A1-expressing cells (ALDH1A1⁺ cells) were detected in the green fluorescence channel. The cells incubated with DEAB were used to establish the baseline fluorescence of these cells (R1) and define the ALDEFLUOR (ALDH1A1)-positive region (R2). B. The ALDH1A1⁺ cell proportion in the bladder cancer cells was significantly lower than that of CD44⁺ cells. The percentage of ALDH1A1⁺ population in the celll lines was from 6.4% to 8.2%. However, the proportion of CD44⁺ cells was from 57% to 72%. C. Merged immunofluorescence imaging showed a high percentage of ALDH1A1⁺ cancer cells positive for CD44 staining. ALDH1A1⁺ cells isolated from HTB-2 cells were positive for ALDH1A1 antibody (green fluorescent staining of the cytoplasm). Fraction of the same cells was positively stained for CD44 as demonstrated by red fluorescent staining of the cell membrane (white arrows). 4',6-diamidino-2-phenylindole (DAPI) was used to stain nuclei. The experiments were undertaken on all bladder cancer cell lines and repeated three times. The Fig.1A and C only showed the result from HTB-2 cell line.