The level of sensitivity to arsenite-induced apoptosis in ATL, Burkitt lymphoma, and myeloid leukemia cell lines correlates with the level of SG-forming activity. (A) HTLV-1–uninfected (Jurkat), HTLV-1–infected (SLB-1; used as a positive control), and ATL-derived (TL-OmI, ED50823, and MT-1) T-cell lines were treated with 0.5 mM of sodium arsenite for 30 minutes and then were stained with anti-USP10 antibodies and Hoechst33258. The SG (%) is presented. (B) HTLV-1–uninfected (Jurkat), HTLV-1–infected (SLB-1), and ATL-derived (TL-OmI, ED50823, and MT-1) T-cell lines were treated with 5 μM of sodium arsenite for 48 hours and then were stained with PI. The proportion of the sub-G1 population (%) (apoptotic cells) was measured using flow cytometry. (C-F) The levels of arsenite-induced SG formation (%) and the proportions of the sub-G1 population (%) in the Burkitt lymphoma (C,D) and myeloid leukemia (ML) cell lines (E,F) were assessed.