Treatment of PPR PDX cells with LCK inhibitors and Dex. (A) Primary cells from 5 different GC-resistant PDX were isolated from mice spleen and treated ex vivo for 48 hr with the indicated concentrations of drugs in the presence of Dex at the molar ratio of 10:1. Cell viability was determined by MTT assay. (B) Primary cells isolated from 3 different PPR PDX were treated with Dex (0.1 μM) and LCK inhibitors (1 μM) alone or in combination for 48 hr. Cell mortality was determined by flow cytometry and annexin V/PI staining. The percentage of dead cells was established after normalizing cells on DMSO-treated cells. Paired t test; *P < .05, **P < .01; n = 3 for all experiments. (C) WB analysis of LCK, LCK Y505, and Src Y416 in PPR PDX cells. Cells were treated with DMSO only (Ctrl), 10 μM of dasatinib, 5 μM of bosutinib, 10 μM of nintedanib, or 10 μM of WH-4-023 for 1 hr.