Apilimod disrupts lysosomal homeostasis and intracellular trafficking. (A) SU-DHL-6 cells were treated with DMSO or 63 nM apilimod for 24 hours and imaged at ×40 magnification. Arrows highlight vacuoles. Image sharpened evenly in order to highlight vacuoles present in floating lymphoma cells. (B) Apilimod induces procathepsin accumulation. Control (CTRL) TFEB-deficient or TFEB-overexpressing CA46 cells were dosed with increasing amounts of apilimod (15-1000 nM) for 24 hours. Lysates were probed with the indicated antibodies. The Pro and Mature forms of cathepsins A and D are indicated. Representative blot is shown from 2 independent experiments. (C) Mean Z-score for top 4 genes from CRISPR apilimod resistance screen. (D) WSU-DLCL2 B-NHL pools with the indicated OSTM1, CLCN7, or nontargeting (NT) sgRNA were treated with 10-point apilimod dose response for 3 days. Data are represented as mean ± SD. Unt, untreated.