Fig. 3.

PIT-1 reduces cell viability, displays preferential effect in PTEN-deficient cells, and synergizes with TRAIL. (A) PIT-1 reduces the viability of multiple cancer cells. Different cancer cell lines were incubated with PIT-1 (12.5–100 μM) for 48 h. Cell viability was determined by using ATP assay. (B) PITs, but not the inactive derivatives, reduce viability of U87MG cells. U87MG cells were incubated with compounds for 48 h, and the representative bright field images of cells are shown. (C) The toxicity of PIT-1 is more pronounced in PTEN-deficient U87MG cells expressing R130M inactive mutant of PTEN compared with the cells expressing wild-type PTEN. After treatment with PIT-1 (25, 50, 100 μM) for 48 h, cell death was analyzed by using Sytox cell death assay. (D) Loss of cell viability caused by PITs, as well as Akt inhibitor, is more pronounced in Akt1-expressing cells compared with the triple knockout cells deficient in all Akt isoforms. Cells were incubated with 100 μM PIT-1, PIT-2, PIT-1i-1, or 10 μM Akt inhibitor VIII for 24 h, followed by analysis of cell viability by using ATP assay. (E) PITs, as well as Akt inhibitor, sensitize U87MG cells to killing by TRAIL. U87MG cells were incubated with 100 μM PIT-1, PIT-2, PIT-1i-1, or 10 μM Akt inhibitor VIII in the presence or absence of 10 ng/mL TRAIL for 24 h, followed by cell viability analysis by using ATP assay.