Fig. 1
From: SWI/SNF catalytic subunits’ switch drives resistance to EZH2 inhibitors in ARID1A-mutated cells
The SWI/SNF catalytic subunits’ switch from SMARCA4 to SMARCA2 accompanies the de novo resistance to EZH2 inhibitors. a, b Parental and GSK126-resistant TOV21G cells were subjected to colony formation (a) to generate dose response curves to GSK126 (b). Arrow points to an ~20-fold increase in GSK126 IC50 in the resistant clones. c Expression of ARID1A, EZH2, H3K27Me3, and a load control β-actin in the indicated cells passaged with or without 5 μM GSK126 for 3 days determined by immunoblot. p.c. positive control ARID1A wild-type RMG1 cells. d, e Immunoprecipition of core SWI/SNF subunit SMARCC1 was separated on a silver stained gel (d), or subjected to LC-MS/MS analysis e. Stoichiometry of the SWI/SNF subunits identified was normalized to SMARCC1. f, g Co-immunoprecipitation analysis using antibodies to core subunit SMARCC1 (f) or SMARCB1 (g) show the switch from SMARCA4 to SMARCA2 in resistant cells. An isotype-matched IgG was used as a control. h, i Sucrose sedimentation (10–50%) assay of SWI/SNF complex from parental (h) or resistant cells (i). j, k Expression of SMARCA4 and SMARCA2 in the indicated cells determined by qRT-PCR (j) or immunoblot (k). l A schematic model: the catalytic subunits from SMARCA4 to SMARCA2 accompanies the de novo resistance to EZH2 inhibitors. Data represent mean ± S.E.M. of three independent experiments (a–c, f–k). P-value was calculated via two-tailed t-test
