SJCRH30 cells were seeded at a density of 5,000 cells/well in BD biocoat poly-D-lysine-coated 96-well plates and incubated at 37 °C overnight. Cells were then treated with 10x solutions of compounds added directly to the growth medium (RPMI 1640 supplemented with 10% FBS) and incubated at 37 °C for the designated time period. Cell nuclei were stained with a 0.1 μg/ml final concentration of Hoechst 33342 (Invitrogen) at the same time as the compound treatment. 10 μl of 10x Hoechst dye in Phosphate Buffered Saline was added directly to the
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growth medium in the wells, and the plate was incubated at 37 °C for the remaining time. Cells had to be stained in two separate steps because Hoechst 33342 is not compatible with the Hands Buffered Saline Solution (HBSS) that is required for the tubulin staining protocol.
To stain microtubules with Tubulin Tracker 488 (TT488), a 500 μM intermediate stock was first prepared by combining 1 mM TT488 (Invitrogen) with an equal volume of 20% Pluronic F-127 in DMSO (Invitrogen). Then a 200 nM TT488 staining solution was prepared from the intermediate stock in HBSS. The growth medium containing the Hoechst dye was removed from the wells, and the cells were rinsed once with warm HBS (100μl per well). The HBSS rinse was replaced with warmed 200 nM TT488 staining solution (100μl per well). The plate was then returned to the 37 °C incubator for 20 minutes before imaging on an Image Xpress Micro system equipped with an enviromental control chamber warmed to 37 °C. Hoeachst 33342 and TT488 staining were visualized using DAPI filter and a FITC filter, respectively. Transmitted light images were also collected to assess cell morphology