Fig. 4.

XPO1 inhibition by KPT-185 induces selective cytotoxicity, apoptosis and cell cycle arrest in PEL cells.

(A) PEL cell lines, BC-1, BCBL-1 and JSC-1, and whole PBMC fraction from normal donors were examined for XPO1 expression by western blot.

(B) Cell viability of BC-1, BCBL-1 and JSC-1 treated cells as measured by MTT-assay, as compared to treated PBMCs as measured by annexin V-PI flow cytometry. Error bars represent standard error of mean, n ≥ 2.

(C) Detection of apoptosis in BC-1, BCBL-1 and JSC-1 cells as early as 24 h after KPT-185 treatment as measured by annexin V-PI flow cytometry. Error bars represent standard error of mean, n ≥ 2.

(D) XPO1 inhibition promotes cell death through a caspase-dependent pathway. PEL cells were treated overnight with KPT-185 in the absence or presence of the general caspase inhibitor Q-VD-OPH. Whole cell extracts were assessed for cleavage of PARP and caspase 3 by western blot analyses.

(E) BC-1, BCBL-1 and JSC-1 cells were treated with different concentrations of KPT-185 and stained with PI (BD Cycletest Plus, BD Biosciences) for cell cycle profiles using flow cytometric analysis. Upon treatment with KPT-185 a clear reduction of the G2/M and S populations is observed while the G0/G1 population increased as well as the subG1 population. Error bars represent standard error of mean, n ≥ 2.