FIGURE 3.

The effects of honokiol on actin polymerization. To evaluate the effects of cisplatin and HNK on the polymerization of actin cytoskeleton, maximum de-polymerization was achieved by incubation of cells in 10 nM of latrunculin B for 4 h. (A) When cells were not allowed to recover, F-actin aggregates (marked with red arrowheads) were observed at the edge of the cells and no elongation of F-actin was observed. (B) When cells were allowed to recover in a complete culture medium supplemented with 10% FBS, a complex actin network can be observed at the leading edge of the cells and stress fibers were also observed. Enlarged image showed elongated actin fiber extended toward the cell edge. (C) After cells were de-polymerized and were allowed to recover (for overnight) in culture medium containing, (C1) 10 nM of latrunculin B and (C2) 10 μM of cisplatin, minimal amount of elongated actin was detected. Enlarged image showed that unlike in full recovery medium, short polymerized actin fiber or aggregates were observed at the cell edge (marked with red arrowheads). However, when HNK was present alone (C3) or was co-present in the recovery medium (C4), the complex actin network and the elongated actin cytoskeleton or stress fiber were observed at the cell edge. (D) F-actin assay demonstrated cisplatin did not caused de-polymerization of actin; and HNK promoted (increased 1.6-fold) the polymerization of actin cytoskeleton. Images presented were representative images, and at least 20 images from each group were taken randomly and assessed. a–c indicated significant (p < 0.05) difference between groups. Lat. B, latrunculin B.