FIGURE 2.

BTG2^/TIS21 enhanced DOXO-induced cell death in human cancer cell lines. A, increase of chromatin condensation in HeLa cells after treatment with DOXO and Ad-TIS21 virus. HeLa cells were infected with adenoviral vector expressing HA-tagged BTG2^/TIS21 (Ad-TIS21-HA) or β-galactosidase (Ad-β-Gal) for 36 h and then treated with DMSO or DOXO (1.0 μg/ml) for 12 h. Hoechst dye staining was performed, and the cells with chromatin condensation were counted. ⋆, p < 0.05 versus DOXO and Ad-β-Gal treated cells; #, p < 0.05 versus DOXO and Ad-BTG2^/TIS21 (10 m.o.i.)-treated cells. The data represent the means and standard deviation from four independent experiments. B, Western blot analysis showing the increased cleavage of PARP and lamin A/C in HeLa cells after infection with Ad-TIS21 virus (50 m.o.i.) compared with the cells treated with DOXO alone or DMSO for 12 h. Anti-HA shows the level of TIS21 expression. C, inhibition of DOXO-induced cell death by lentivirus infection containing short hairpin-BTG2 sequences. HeLa cells were infected either with empty vector (Con) or sh-BTG2 virus (H4 and H5), and knockdown of BTG2 expression and the accompanying inhibition of cell death were examined then by RT-PCR and Western blot analyses, respectively. RT-PCR analysis of the level of BTG2 mRNA was normalized to the level of glyceraldehyde-3-phosphate dehydrogenase mRNA, and the level was indicated at the bottom of the data. Note inhibition of BTG2 expression by sh-RNA (H5) more than 60%. D, enhanced cell death by Ad-TIS21 infection in liver cancer cells. Huh7, HepG2, and Hep3B cells were infected with Ad-TIS21 virus and then treated with either DMSO or DOXO (1.0 μg/ml) for 36 h. The cleavages of PARP and lamin A/C were examined by Western blotting. Note the increase of PARP and lamin A/C cleavages. The data represent a typical result from four independent experiments.