Increasing procaspase 8 expression using repurposed drugs to induce HIV infected cell death in ex vivo patient cells

Abstract

HIV persists because a reservoir of latently infected CD4 T cells do not express viral proteins and are indistinguishable from uninfected cells. One approach to HIV cure suggests that reactivating HIV will activate cytotoxic pathways; yet when tested in vivo, reactivating cells do not die sufficiently to reduce cell-associated HIV DNA levels. We recently showed that following reactivation from latency, HIV infected cells generate the HIV specific cytotoxic protein Casp8p41 which is produced by HIV protease cleaving procaspase 8. However, cell death is prevented, possibly due to low procaspase 8 expression. Here, we tested whether increasing procaspase 8 levels in CD4 T cells will produce more Casp8p41 following HIV reactivation, causing more reactivated cells to die. Screening 1277 FDA approved drugs identified 168 that increased procaspase 8 expression by at least 1.7-fold. Of these 30 were tested for anti-HIV effects in an acute HIVIIIb infection model, and 9 drugs at physiologic relevant levels significantly reduced cell-associated HIV DNA. Primary CD4 T cells from ART suppressed HIV patients were treated with one of these 9 drugs and reactivated with αCD3/αCD28. Four drugs significantly increased Casp8p41 levels following HIV reactivation, and decreased total cell associated HIV DNA levels (flurbiprofen: p = 0.014; doxycycline: p = 0.044; indomethacin: p = 0.025; bezafibrate: P = 0.018) without effecting the viability of uninfected cells. Thus procaspase 8 levels can be increased pharmacologically and, in the context of HIV reactivation, increase Casp8p41 causing death of reactivating cells and decreased HIV DNA levels. Future studies will be required to define the clinical utility of this or similar approaches.

Repurposing Dihydropyridines for Treatment of Helicobacter pylori Infection

“…Developing a new chemical entity drug and delivering it to the market, known as de novo drug discovery, is a time-consuming and expensive process with increasing regulatory requirements and a high risk of failure-all of which could make the pharmaceutical industry a less desirable choice for investors. Nowadays, drug repurposing has become a successful strategy to fast-track therapeutic agents for the treatment of several emerging or rare diseases, such as AIDS, Alzheimer's disease and cancer [10,[34][35][36][37][38][39][40], but also infections with multidrug-resistant strains of clinically relevant pathogens [9,[41][42][43][44].…”

HIV-1 release requires Nef-induced caspase activation

“…The current paradigm assumes HIV-1 infection-induced caspases activation is part of host anti-viral response to kill infected T cells [8], thus detrimental to the viral expansion. This prompted a treatment strategy to stimulate procaspase8 expression and to enhance apoptosis of latency reversal agents (LRA-kick) reactivated viral reservoir cells, as some of the stimulated viral reservoir cells resisted apoptotic cell death [67]. Our findings of viral release required caspase activation suggests, however, that caspases activation is not detrimental but potentially beneficial to the viral expansion.…”

Mechanisms of Human Immunodeficiency Virus-Associated Lymphocyte Regulated Cell Death

“…125 Further understanding of how HIVinfected cells can die, and why some infected cells do not die, can inform strategies to modulate apoptosis and other signaling pathways to promote death of reactivated cells. 126 Indeed, early success in increasing cell death in reactivated, infected cells in vitro and ex vivo has been shown by targeting the DExD/H-box helicase 58 (DDX58 or RIG-1) pathway 127 ; the intrinsic apoptosis pathway 63,128,129 ; the extrinsic apo-ptosis pathway 130 ; and autophagy-dependent cell death. 131 These strategies will likely generate better results when effective HIV-1-specific cytotoxic T cell response is activated concomitantly.…”