Figure 4.

In vitrosecretion of h-sAPPα by SH-SY5Y human neuroblastoma cells and its modulation by pharmacologic agents.A: Various numbers of SH-SY5Y human neuroblastoma cells (between 10⁴ and 5 × 10⁴) were plated in 96-well plates in 0.1 ml final volume. After a 24 hours incubation, medium was collected and 5 μl of each sample was tested in duplicate in the h-sAPPα assay. B: 3 × 10⁴ SH-SY5Y cells were plated in 96-well plates in 0.1 ml final volume. Medium was collected after incubations of 6 hours, 18 hours, 24 hours or 36 hours, 5 μl of each sample was tested in duplicate in the h-sAPPα assay. C: 3 × 10⁴ SH-SY5Y cells were plated in 96-well plates in 0.1 ml final volume. The next day, the conditioned medium was discarded and replaced by the same medium containing 1% N2 in place of FCS. Various concentrations of PDBu (0.01 − 1 μM) were then added. After an incubation of 24 hours, medium was collected and 5 μl of each sample was tested in duplicate in the h-sAPPα assay. D: 3 × 10⁴ SH-SY5Y cells were plated in 96-well plates in 0.1 ml final volume. The next day, the conditioned medium was discarded and replaced by the same medium containing 1% N2 in place of FCS. Then, GF109203 (10 μM) and TAPI 0 (30 μM) were added and PDBu (0.3 μM) was added 1 hour later. After a 24 hour incubation, the medium was collected and 5 μl of each sample was tested in duplicate in the h-sAPPα assay. ***: p < 0.001.