An inhibitor of FGF or VEGF receptors eliminates the superior effect of TA-316 on imMKCL proliferation. imMKCLs cultured with rhTPO (50 ng/mL), TA-316 (200 ng/mL), eltrombopag (1000 ng/mL), or DMSO (0.05%). (A) Cells were collected on day 11 (genes on). mRNA expressions of VEGFA and FGF2 (genes on) were evaluated using Taqman PCR assays. GAPDH served as an internal control. (B) FGFR antagonist PD173074 (100 nM; WAKO), VEGFR antagonist axitinib (5 nM; Toronto Research Chemicals, Toronto, Canada), or epithelial growth factor receptor antagonist gefitinib (1 μM, Santa Cruz Biotechnology, Dallas, TX) was added to the imMKCLs, which were cultured with TA-316 (200 ng/mL) for 4 days (genes on). Cell proliferation was assessed based on 0.4% Trypan blue staining (Thermo Fisher Scientific). Data represent the mean and SD; *P < .05, **P < .01.