The ACER2/ SMPDL3B axis regulates HCC cell growth via S1P. A‐D, Hunh‐7 cells under the indicated treatments were lysed. One portion of the lysate was subjected to an S1P ELISA (A, B). Error bars represent the SD from 3 independent experiments, and statistical significance was analyzed using Student t test (*P < .05; **P < .01; ***P < .001). The other portion of the lysate was analyzed by western blotting with the indicated antibodies (C, D). E, F, SKII rescued the cell growth mediated by ACER2 overexpression (E) or SMPDL3B overexpression in the presence of ACER2 knockdown (F). Error bars represent the SD from 3 independent experiments, and statistical significance was analyzed using Student t test (#, +P < .05; **, ## or ++P < .01; ***, ### or +++P < .001). plus sign: ACER2 shRNA + SMPDL3B vs ACER2 shRNA + SMPDL3B+SKII or GFP‐ACER2 + NC siRNA vs GFP‐ACER2 + NC siRNA + SKII (applicable below)