Figure 2.

Treatment with MRX-2843 inhibits activation of MERTK in ETP-ALL cell lines in a dose-dependent manner. (A–D) Loucy (A,C) and PEER (B,D) cells were treated with the indicated concentrations of MRX-2843 or vehicle (DMSO). (A,B) After 1 h, cells were treated with phosphatase inhibitor; then, cell lysates were prepared, MERTK protein was immunoprecipitated, and pMERTK and total MERTK were detected by immunoblot. Images shown are representative of results obtained in three independent experiments. (C,D) Proteins were quantitated by densitometry and pMERTK/MERTK ratios relative to vehicle control were determined. IC₅₀ values were calculated by nonlinear best-fit regression. Mean values and standard errors derived from 3–4 independent experiments are shown. (E,F) PEER cells were treated with 300 nM MRX-2843 or vehicle with or without Gas6 ligand, and phosphorylated and total STAT5 proteins were detected by immunoblot. Images shown are representative of results obtained in at least three independent experiments. (F) Proteins were quantitated by densitometry and pSTAT5/STAT5 ratios were determined relative to vehicle treatment. Mean values and standard errors derived from six independent experiments are shown. * p < 0.05 and ** p < 0.01 by paired t-test.