Our criteria GSK458 order for active compounds to be further investigated was arbitrarily set as Δ Fn = 50-100% quenching for iron uptake inhibitors and < -50% quenching for iron uptake facilitators. 55Fe uptake into K562 cells 3 × 105 K562 cells in 300 μl NaCl-Hepes-0.1% BSA were incubated for 30 min with test compound at various concentrations as indicated in a humidified 37°C incubator with 5% CO2. A mixture of 55Fe- and AA was then added for a final concentration of 1 μM 55Fe -1 mM AA and the cells incubated for an additional 60 min. The reaction was stopped by the addition of ice-cold quench Ralimetinib solubility dmso buffer (NaCl-Hepes
with 2 mM EDTA) followed by extensive washing of the cells which were then dispersed in scintillation fluid and 55Fe Vactosertib nmr radioactivity determined in a Tri-carb 2900 TR liquid scintillation analyzer (Packard BioScience Company, Meriden, CT). Preparation of medium containing 10%
FCS with iron-saturated Tf Iron on the Tf in FCS was removed from the Tf by lowering the pH to 4.5 followed by dialysis against 0.1 M citrate buffer, pH 4.5, in the presence of Chelex for 16 hours, and dialyzed again against HEPES buffered saline, pH 7.4, in the presence of Chelex. FeNTA (1:2 molar ratio for Fe: NTA) was then added to the now iron-free FCS at 1 mM final concentration followed by extensive dialysis against HEPES buffered saline, pH 7.4. The resulted FCS containing iron-saturated Tf was added into RPMI1640 to make the medium containing 10% iron-saturated FCS. Western blot analysis of ferritin, TfR, and HIF-1α and -2α PC-3 cells were plated into 6-well plates at cell
density of 5 × 105 cells/well for overnight attachment before addition of test compound or vehicle control for 16 hours. The cells were until then lysed with RIPA buffer (50 mM Tris-HCl, 1% NP-40, 0.25% Na-deoxycholate, 150 mM NaCl, 1 mM EDTA, pH 7.4) and the lysates separated on SDS-PAGE with subsequent transfer to nitrocellulose for western blot analysis using the following antibodies: mouse anti-human ferritin-heavy chain, mouse anti-human TfR, anti-HIF-1α or -2α, and rabbit anti-human β-actin. Results were quantitated by densitometry and relative densitometric units expressed as the ratio of protein of interest to actin. 55Fe uptake and transport in Caco2 cells Caco2 cells were seeded in 6.5 mm bicameral chambers in 24-well plates, grown in 10% FCS-minimum essential medium for ~2 week to reach a transepithelial electrical resistance (TEER) of 250 .cm2. The cells were incubated in serum-free DMEM with 0.1% BSA overnight and the inserts then transferred to fresh 24-well plates with the basal chambers containing 700 μL of 20 μM Apo-Tf in DMEM. Test compound at concentrations of 0-100 μM in a total volume of 150 μl were added to the top chamber, incubated for 60 min at 37°C, 5% CO2 incubator, followed by the addition of 55Fe to the top chamber at a final concentration of 0.125 μM 55Fe in 1 mM AA.