Fig 2. TQ potentiates the apoptotic effect of bortezomib causing accumulation of U266 cells in sub-G1 phase, activates caspase-3 and induce PARP cleavage.

A, U266 cells were synchronized by serum starvation and then exposed to TQ (5 μM), bortezomib (20 nM) and a combination of both for 24 h at 37°C. The cells were then washed, fixed, stained with PI, and analyzed for DNA content by flow cytometry. B, U266 cells were synchronized by serum starvation and then exposed to TQ (5 μM), bortezomib (20 nM) and a combination of both for 24 h. Cells were incubated with anti-Annexin V antibody conjugated with FITC, followed by PI and then analyzed with a flow cytometry to detect early apoptotic effects. C, U266 cells were treated with TQ (5 μM), bortezomib (20 nM) and a combination of both for 24 h at 37°C. Whole-cell extracts were prepared, separated on SDS-PAGE, and subjected to Western blot analysis using antibody against procaspase-3 and cleaved caspase-3. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. D, U266 cells were treated with TQ (5 μM), bortezomib (20 nM) and a combination of both for 24 h at 37°C. Whole-cell extracts were prepared, separated on SDS-PAGE, and subjected to Western blot analysis using antibody against PARP. The same blots were stripped and reprobed with β-actin antibody to show equal protein loading. Results typical of two independent experiments are shown.