Histone deacetylase inhibitor chidamide promotes reactivation of latent human immunodeficiency virus by introducing histone acetylation

Highly active antiretroviral therapy can reduce the human immunodeficiency virus (HIV) viral load in the plasma to undetectable levels. However, because of the presence of latent HIV reservoirs, it is difficult to completely eradicate HIV in infected patients. Our objective was to assess the potency of chidamide, a novel histone deacetylase inhibitor recently approved for cancer treatment by the China Food and Drug Administration, to reactivate latent HIV-1 via histone acetylation. Viral reactivities of chidamide were accessed in 2 latent HIV pseudotype virus cell reporter systems (J-Lat Tat-green fluorescent protein clone A72 and TZM-bl), a latently infected full-length HIV virus cell system (U1/HIV), and resting CD4(+) T cells from 9 HIV-infected patients under highly active antiretroviral therapy with undetectable viral load. Chidamide was able to increase HIV expression in each cell line, as evidenced by green fluorescent protein, luciferase activity, and p24, as well as to reactivate latent HIV-1 in primary CD4(+) T cells of HIV-infected patients. Histone acetylation adjacent to the HIV promoter in A72 cells was determined by chromatin immunoprecipitation. Chidamide was able to increase histone H3 and H4 acetylation at the HIV promoter. In brief, chidamide induced the reactivation of latent HIV in pseudotype virus reporter cells, latently infected cells, and primary CD4(+) T cells, making this compound an attractive option for future clinical trials.