Figure 4.

ROCK2 deletion does not inhibit doxorubicin-induced cell detachment. (a) Representative images of rhodamine-phalloidin staining for F-actin (red) and DAPI staining (blue) of WT and ROCK2^−/− cells treated with 3 μM doxorubicin for 16 h. Actomyosin contractile rings are indicated with white arrow, and folded periphery membranes with white arrowheads. Bar, 50 μm. (b) Cells showing formation of cortical contractile ring structure or with folded periphery membrane were counted and expressed as percentage of total cells under indicated conditions. For each treatment, over 500 cells were counted. (c) Floating cells and attached cells were separately collected and counted at indicated time points and dosages of doxorubicin. Floating cell ratio was expressed as percentage of total cells (floating plus attached cells) under indicated conditions. (d and e) Representative image (top) and quantitative analysis (bottom) of western blot of p-MLC2 and MLC2, or p-cofilin and cofilin in cell lysates from attached WT and ROCK2^−/− MEFs treated with 3 μM doxorubicin for 30 min. *P<0.05 versus control of the same genotype. ^#P<0.05 versus WT under the same treatment condition