Figure 4.

Exogenous SAMHD1 expression in HuT78 cells significantly increases Fas-L induced apoptosis and caspase-3/7 activity. (A) HuT78 vector control and SAMHD1-expressing cells were treated with 100 ng/ml Fas-L for 48 hours. After 48 hours of treatment, all the cells in triplicate were stained with annexin V-PE and 7-AminoactinomycinD (7-AAD) followed by flow cytometry. Representative flow cytometric profiles are presented (left panel). The percentage of non-apoptotic cells, early apoptotic cells, and late apoptotic cells were quantified as presented (right panel). (B) HuT78 vector control and SAMHD1-expressing cells were treated with 100 ng/ml Fas-L for 48 hours. Post-treatment, 1 × 10⁴ cells per cell line were collected in triplicate and incubated in 100 µl of Caspase-Glo 3/7 reagent at room temperature in dark for 1 hour. Caspase-3/7 activity was then determined by measuring luminescence values. C, HuT78 vector control and SAMHD1-expressing cells were treated with Fas-L (100 ng/ml) for 48 hours. Post-treatment, cell lysates from all cell lines were collected and immunoblotting was performed using the antibodies to caspase-8, caspase-3, PARP, and GAPDH (loading control). All the data presented are representative of 3 independent experiments. A–B, ***, p < 0.001.