Figure 3
From: Altered sialidase expression in human myeloid cells undergoing apoptosis and differentiation
Total NEU Activity in HL60 and dHL60 Cells. (A, B) HL60 cells (2.5 × 107 cells/assay) were cultured for increasing times in the presence of DMF or medium alone and assayed for NEU activity for the fluorogenic substrate, 4-MU-NANA (A) and cell viability (B). (C) Sialidase activity in (A) was normalized to cell viability in (B). (D) Increasing equivalent cell numbers of HL60 and dHL60 cells were assayed for NEU activity. (E) HL60 cells (2 × 107 cells/sample) in the presence of increasing concentrations of the NEU inhibitor, 2DN, or the KDO negative control, were assayed for NEU activity. (F, G) HL60 cells were cultured for 7 days in the presence of DMF, DMSO, RA, or medium alone. Equivalent HL60 and dHL60 cell numbers (2 × 107 cells/sample) were assayed for NEU activity (F) and cell viability (G). (H) NEU activity in (F) was normalized to cell viability at 5 days in (G). (A–F, H) Vertical bars or symbols represent mean ± SE NEU activity expressed as arbitrary fluorescence units (A, D, E, and F) or mean ± SE cell viability expressed as cellular uptake of MTT (B and G). *, significantly increased compared with NEU activity or viability in equivalent numbers of dHL60 cells at p < 0.05. **, significantly decreased compared with NEU activity or cell viability in nondifferentiated HL60 cells (A, B, D, F, G) or HL60 cells in the absence of 2DN (E) at p < 0.05. (I, J) HL60 and DMF-differentiated HL60 cells were stained with fluoroprobe-labeled anti-CD11c (I, J), anti-CD32 (J), and anti-gp91phox (J) antibodies, along with 7-AAD to exclude dead cells. (I) Histograms of CD11c expression in HL60 and dHL60 cells and (J) the mean fluorescence intensity (MFI) for each fluoroprobe for live cells. *, significantly increased MFI compared with the MFI for the same fluoroprobe for nondifferentiated HL60 cells. The data generated in each panel represents experiments performed on ≥ 2 independent occasions.
