Knocking down FAIM suppresses cancer cell proliferation through inducing autophagy. (A and B) A549 (A) and H1299 (B) cells were transfected with control siRNA (CON-si) or FAIM siRNAs (FAIM-si1, FAIM-si2). Forty-two h later, the cells were treated with or without 20 μM chloroquine (CQ) for 6 h. Immunofluorescence was performed using LC3B antibody and then analyzed by fluorescence microscopy (Olympus IX83). Scale bar: 30 μm (Left panel). The cell numbers with LC3B puncta were counted under 200× magnification. *, P < 0.05; **, P < 0.01; ***, P < 0.001 (Right panel). (C) A549 cells were transfected with control siRNA (CON-si) or FAIM siRNAs (FAIM-si1, FAIM-si2). Forty-eight h later, the cells were lysed and western blot was performed to detect the expression of the indicated proteins. (D) A549 cells were transfected with control siRNA (CON-si) or FAIM siRNAs (FAIM-si1, FAIM-si2). Forty-two h later, the cells were treated with or without 20 μM chloroquine (CQ) for 6 h. Western blot was used to detect the expression of the indicated proteins. (E and F) A549 (E) and H1299 (F) cells were transfected with control siRNA (CON-si) or FAIM siRNAs (FAIM-si1, FAIM-si2). Twenty-four h later, cells were seeded in 24-well plates at 5000 cells per well in 0.5 ml complete culture medium treat with or without Chloroquine (CQ). On the 6th day, cells were fixed in 3.7% formaldehyde and stained with 0.1% crystal violet. Data represent the average of three independent experiments (mean ± SD). **, P < 0.01.