The implementation of combined antiretroviral therapy
(cART) has
rendered HIV-1 infection clinically manageable and efficiently improves
the quality of life for patients with AIDS. However, the persistence
of a latent HIV-1 reservoir is a major obstacle to achieving a cure
for AIDS. A “shock and kill” strategy aims to reactivate
latent HIV and then kill it by the immune system or cART drugs. To
date, none of the LRA candidates has yet demonstrated effectiveness
in achieving a promising functional cure. Interestingly, the phosphorylation
and activation of antiapoptotic Bcl-2 protein induce resistance to
apoptosis during HIV-1 infection and the reactivation of HIV-1 latency
in central memory CD4+ T cells from HIV-1-positive patients.
Therefore, a Bcl-2 antagonist might be an effective LRA candidate
for HIV-1 cure. In this study, we reported that a pan-Bcl-2 antagonist
obatoclax induces HIV-1 reactivation in latently infected cell lines in vitro and in PBMCs/CD4+ T cells of HIV-infected
individuals ex vivo. Obatoclax promotes HIV-1 transcriptional
initiation and elongation by regulating the NF-κB pathway. Obatoclax
activates caspase 8 and does not induce the phosphorylation of the
antiapoptotic protein Bcl-2 in latent HIV-1 infected cell lines. More
importantly, it preferentially induces apoptosis in latently infected
cells. In addition, obatoclax exhibited potent anti-HIV-1 activity
on target cells. The abilities to reactivate latent HIV-1 reservoirs,
inhibit HIV-1 infection, and induce HIV-1 latent cell apoptosis make
obatoclax worth investigating for development as an ideal LRA for
use in the “shock and kill” approach.