Live Cell Imaging Supports a Key Role for Histone Deacetylase as a Molecular Target during Glioblastoma Malignancy Downgrade through Tumor Competence Modulation

Figure 1

HDAC blockade leads to tunneling tube formation through F-actin cytoskeleton stabilization. (A–L) Time-lapse video microscopy of iHDAC-treated U87-MG cells during 72 h identified the formation of tunneling tubes starting at 20 h after treatment (A, white arrow; red asterisks evidence cell body). Membrane extensions of one cell touch the cell body of neighboring cells, interconnecting tumor cells starting at 35 h after treatment (D). At this time point, transitory membrane protrusions can be noticed (D, white head arrows). As the cell body migrates, it elongates (D, red asterisk) and the transitory membrane protrusion is retracted (E, black head arrow) at the same time that it is possible to note the formation of gondolas along the tunneling tube (, black head arrow). The tunneling tube now reaches a neighboring cell (E–G). After losing contact with the neighboring cell, the membrane filament completely retracts (H–L, white head arrow). It was possible to estimate that the membrane filament remained stretched for about 6 hours after loss of contact with the neighboring cell (I–L). iHDAC-treated cells presented type I (actin rich) and type II nanotubes (actin and tubulin rich) which also harbor gondolas (M–O, white head arrows). The elongation index was measured and iHDAC-treated cells (Q, R) were more elongated than DMSO group (P, R). Nanotubes formed in iHDAC-treated cells were more stable and organized than in the control group as found upon F-actin fibrillar structure and anisotropy analysis (S).