American Society of Hematology

Figure 2

$Figure 2. HDACIs have no effect on platelet apoptosis or half-life. (A) Cohorts of C57BL/6 Bax−/−Bak−/− (dKO) and wild-type (WT) mice were treated with daily IP panobinostat 10 mg/kg (Pan) or vehicle. At the indicated time points, platelet counts were taken from 3 mice in each group. Platelet number in both HDACI-treated groups decreased with treatment, indicating that TCP is independent of apoptosis. Error bars represent SEM. P values reflect results between Bax−/−Bak−/− mice treated with panobinostat and vehicle at the indicated time points using 2-tailed unpaired t tests. (B) Flow cytometric analysis of circulating platelets for surface biotin and thiazole orange in C57BL/6 mice. Cohorts of mice were injected with 600μg of NHS-biotin and then treated with either daily IP panobinostat 10 mg/kg (top row) or vehicle (bottom row). Platelets were gated by side and forward scatter and CD41 staining. Platelets were then analyzed for uptake of thiazole orange (Alexa Fluor 488) and surface biotin (APC-A), allowing the calculation of biotinylated platelet number and new platelet fractions. (C) Mice injected with NHS-biotin and treated with (i) panobinostat 10 mg/kg or vehicle or (ii) romidepsin 1 mg/kg (Romi) IP daily or vehicle underwent flow cytometric analysis as in panel B, and also had a matched, automated full blood examination. The absolute biotinylated platelet count for each mouse was calculated and plotted. Error bars represent SEM. Results were compared using linear regression analysis. (D) C57BL/6 mice injected with NHS-biotin and treated with daily IP panobinostat 10 mg/kg or vehicle, a carboplatin 100 mg/kg single dose, or daily IP ABT-737 75 mg/kg underwent flow cytometric analysis as in panel B, and also had a matched, automated full blood examination taken. The absolute biotinylated platelet count for each mouse was calculated and plotted. Error bars represent SEM. (E) C57BL/6 mice injected with NHS-biotin and treated with daily IP panobinostat 10 mg/kg or vehicle, a carboplatin 100 mg/kg single dose, or daily IP ABT-737 75 mg/kg underwent flow cytometric analysis as above and also had a matched, automated full blood examination taken. The nonbiotinylated reticulated platelet fraction was calculated and plotted for each mouse. Error bars represent SEM.$

HDACIs have no effect on platelet apoptosis or half-life. (A) Cohorts of C57BL/6 Bax^−/−Bak^−/− (dKO) and wild-type (WT) mice were treated with daily IP panobinostat 10 mg/kg (Pan) or vehicle. At the indicated time points, platelet counts were taken from 3 mice in each group. Platelet number in both HDACI-treated groups decreased with treatment, indicating that TCP is independent of apoptosis. Error bars represent SEM. P values reflect results between Bax^−/−Bak^−/− mice treated with panobinostat and vehicle at the indicated time points using 2-tailed unpaired t tests. (B) Flow cytometric analysis of circulating platelets for surface biotin and thiazole orange in C57BL/6 mice. Cohorts of mice were injected with 600μg of NHS-biotin and then treated with either daily IP panobinostat 10 mg/kg (top row) or vehicle (bottom row). Platelets were gated by side and forward scatter and CD41 staining. Platelets were then analyzed for uptake of thiazole orange (Alexa Fluor 488) and surface biotin (APC-A), allowing the calculation of biotinylated platelet number and new platelet fractions. (C) Mice injected with NHS-biotin and treated with (i) panobinostat 10 mg/kg or vehicle or (ii) romidepsin 1 mg/kg (Romi) IP daily or vehicle underwent flow cytometric analysis as in panel B, and also had a matched, automated full blood examination. The absolute biotinylated platelet count for each mouse was calculated and plotted. Error bars represent SEM. Results were compared using linear regression analysis. (D) C57BL/6 mice injected with NHS-biotin and treated with daily IP panobinostat 10 mg/kg or vehicle, a carboplatin 100 mg/kg single dose, or daily IP ABT-737 75 mg/kg underwent flow cytometric analysis as in panel B, and also had a matched, automated full blood examination taken. The absolute biotinylated platelet count for each mouse was calculated and plotted. Error bars represent SEM. (E) C57BL/6 mice injected with NHS-biotin and treated with daily IP panobinostat 10 mg/kg or vehicle, a carboplatin 100 mg/kg single dose, or daily IP ABT-737 75 mg/kg underwent flow cytometric analysis as above and also had a matched, automated full blood examination taken. The nonbiotinylated reticulated platelet fraction was calculated and plotted for each mouse. Error bars represent SEM.

This Feature Is Available To Subscribers Only