Fig. 9
From: Apoptosis-induced activation of HIV-1 in latently infected cell lines
Apoptosis-triggered HIV-1 activation is caspase dependent. U1 cells were pre-treated with increasing concentrations (0-100 μM) of the pan-caspase inhibitor, Z-VAD-FMK for 2 h. U1 cells were treated with pro-apoptotic agents; (a) etoposide, (b) doxorubicin and (c) vincristine to induce apoptosis for 36 h. Cells were stained with Annexin V and 7-AAD and assayed for apoptosis (solid line) using flow cytometry. HIV-1 activation was assessed by quantification of unspliced viral RNA using qRT-PCR and represented as fold change compared cells treated with DMSO-containing medium without cytotoxic agents (dashed line). Culture supernatants were assayed for virus released by determining amount HIV p24-antigen (ng/ml) (dotted line) p24 ELISA. Treatment with all cytotoxic agents led to apoptosis-mediated activation of HIV-1 in U1 cells, which was blocked in a dose-dependent manner by the caspase inhibitor, Z-VAD-FMK. (d and e) Cells were treated with PMA as a positive control for HIV-1 activation through the conventional pathway. The data represented are the mean ± standard deviation (n = 3)