Expansion of PDX models will be required to cover all the main breast cancer ph

The phagocytosis efficiency was only slightly enhanced by a high external calcium level of 4 mM in MH S cells, if thapsigargin was not present. Activated U937 cells showed only a significant increase in phagocytosis MK-0457 clinical trial at an external calcium level of 4 mM if 10 nM thapsigargin was present. This cell type was not influenced by external calcium levels, if thapsigargin was not present in cell medium. Furthermore, thapsigargin did not elevate the phagocytosis efficiency in standard cell culture medium RPMI1640 with 10% FCS, FCS free RPMI1640 and in calcium free HBSS buffer. Understanding the mechanisms of bead uptake by macrophages is essential for the therapeutic nano and microparticle delivery to macrophages as a potential ap proach for targeted drug delivery.

Results Influence of thapsigargin concentration and medium composition on phagocytosis The influence of the thapsigargin concentration on the phagocytosis of the fluorescent beads by differentiated Motesanib 溶解度 U937 and MH S cells was analyzed in RPMI1640 medium supplemented with 10% FCS. An initial number of 5 × 105 cells were incubated with in creasing concentrations of thapsigargin prior to the in cubation with 1 × 107 beads. A number of 1 × 104 cells were analyzed by flow cytometry for increased fluores cence intensity caused by the uptake of particles. The graph in Figure 1 shows that a thapsigargin concentra tion in the range of 10 nM to 1 uM did not significantly influence the phagocytosis by U937 cells and MH S cells.

The effect of 10 nM thapsigargin on the phagocytosis efficiency of differentiated U937 cells was Nutlin-3 investigated in RPMI1640 medium with 10% FCS in RPMI1640 medium without FCS and in ex ternal Ca2 free, Mg2 free and FCS free HBSS buffer. No significant influence of 10 nM thapsigargin was de termined on the phagocytosis efficiency of differentiated U937 cells in all three medium compositions. On the other hand, the comparison of the phagocytosis efficiencies in different media showed significant differ ences for phagocytosis of the beads by differentiated U937 cells. Figure 3 shows that the lowest phagocytosis efficiency was achieved in Ca2 free and Mg2 free HBSS buffer, followed by the value achieved in RPMI1640 medium without FCS. The highest phagocytosis rate was achieved in FCS containing RPMI1640 medium.

The concentration of 10 nM thapsigargin did not in fluence the phagocytosis efficiency of MH S cells for the beads significantly in any of the medium compositions used to determine the phagocytosis efficiency in this study. However, in contrast to the differenti ated U937 cells, the phagocytosis efficiency of MH S cells in HBSS buffer did not significantly differ from the phagocytosis efficiency in FCS free RPMI1640 medium. In FCS containing RPMI1640 medium, the MH S cells showed a significantly higher phagocytosis efficiency than in HBSS buffer or in FCS free RPMI1640 medium. Influence of increasing external calcium ion concentrations on phagocytosis To determine the effect of external calcium on the phago cytosis efficiency of macrophages, the reference cell lines MH S and differentiated U937, were incubated in Ca2 free, Mg2 free and FCS free HBSS buffer for one hour.