Fig. 5.

FGF2 renders the MB cells insensitive to RA treatment. (A) FGF-2 was capable of overriding the growth-inhibitory effect of 9-cis RA on D425 cells. D425 cells were incubated with 20 ng/mL of EGF, 10 ng/mL of FGF-2 in DMEM media containing 10% FBS or stem/progenitor cell media for 96 hours in the presence of 1 µM 9-cis RA. Viable cells were determined by cell proliferation assay reagent WST-1 and graphed in percentage to the control that was cultured without 9-cis RA. (B) FGFR inhibitor PD173074 restored the RA-sensitivity of D425 cells. D425 cells were incubated for 96 hours with the indicated combinations of 9-cis RA (1 µM) and FGF2 (10 ng/mL) in the presence of the FGFR inhibitor PD173074 at the concentration from 0 to 1 µM. Viable cells were determined by WST-1 and graphed in percentage to the control that was cultured without 9-cis RA, FGF2, and PD173074.