Nicotinamide activates latent HIV-1 ex vivo in ART suppressed individuals, revealing higher potency than the association of two methyltransferase inhibitors, chaetocin and BIX01294

ABSTRACT Background: Latent HIV-1 is a major hurdle in obtaining HIV-1 sustained virological remission (SVR). Here we explored histone deacetylation inhibition property of nicotinamide (NAM; n = 17) for the first time in comparison to a combination of methyltransferase inhibitors (MTIs; Chaetocin and BIX01294; n = 25) to reactivate latent HIV ex vivo in CD8-depleted PBMCs from antiretroviral treated aviremic individuals. Results: NAM reactivated HIV-1 from 13/17 (76.4%) samples compared to 20/25 (80.0%) using MTIs with mean viral load (VLs) of 4.32 and 3.22 log10 RNA copies/mL, respectively (p = 0.004). Mean purging time after NAM and MTIs stimulation was 5.1 and 6.75 days, respectively (p = 0.73). Viral purging in autologous cultures exhibited blunted HIV recovery with fluctuating VLs followed by a complete viral extinction when expanded in allogenic system. Electron microscopy from five supernatants revealed anomalous viral particles, with lack of complete viral genomes when characterized by ultradeep sequencing through metagenomics approach (n = 4). Conclusion: NAM alone was more potent HIV-1 activator than combination of MTIs, with potential of clinical use.

Selectively enhancing radiosensitivity of cancer cells

The radiotherapy modulators used in clinic have disadvantages of high toxicity and low selectivity. For the first time, we used the

Effect and mechanism of suberoylanilide hydroxamic acid on fear extinction in mice with chronic so-cial defeat stress / 中华行为医学与脑科学杂志

Objective To investigate the effect and mechanism of suberoylanilide hydroxamic acid (SAHA) on the fear extinction in mice with chronic social defeat stress (SD). Methods Fifty-six male C57BL/6J mice aged 7-8 weeks were randomly divided into control group,social defeat group,control-SAHA group and social defeat-SAHA group to investigate the effect of SAHA and social defeat group,social defeat-AAV BDNF group and social defeat-AAV blank group to investigate the effect of BDNF. Fear extinction in mice was evaluated by fear conditioning test (FC). The levels of BDNF and HDAC2 in mice hippocampus were detected by Western blot (WB). The expression of BDNF-overexpressing virus in hippocampus of mice was detected by immunofluorescence assay. Results (1) Compared with control group,fear extinction in the social defeat group was significantly decreased (P<0. 05). Compared with control group, the level of HDAC2(0. 50±0. 02) in the social defeat group was significantly increased (P<0. 001),while the level of BDNF(0. 16 ± 0. 03) was significantly decreased (P<0. 001) in the social defeat group. ( 2) After using SAHA,fear extinction of mice significantly improved (P<0. 05). Compared with control group,the level of HDAC2 (0. 26±0. 02) in the control-SAHA group was significantly decreased(P<0. 001),and the level of BDNF (0. 40±0. 03) was significantly increased (P<0. 001). Compared with social defeat group,the level of HDAC2 (0. 39±0. 03) in the social defeat-SAHA group was significantly decreased (P<0. 001),and the lev-el of BDNF (0. 28±0. 01) was significantly increased (P<0. 001). (3)After injection BDNF-overexpressing virus,fear extinction was significantly improved(P<0. 05). Conclusion SAHA can enhance fear extinction in mice with chronic social defeat stress and its mechanism may be related to the up-regulation of BDNF ex-pression in hippocampus by inhibiting HDAC2 in hippocampal.

Protective effect of the histone deacetylase inhibitor ACY1215 against brain edema in mice with acute liver failure / 中华肝脏病杂志

Objective@#To investigate the protective effect of ACY1215 (Rocilinostat), a histone deacetylase inhibitor, against brain edema in mice with acute liver failure.@*Methods@#Lipopolysaccharide combined with D-galactosamine was used to establish a mouse model of acute liver failure, and ACY1215 was used for intervention. The effect of ACY1215 on histopathological changes of the liver was observed after 24 hours, as well as the changes in alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood ammonia, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), brain water content, blood-brain barrier structure, NF-κB-p65, histone, acetylated histone, and TNF-α mRNA in brain tissue.@*Results@#The mice with acute liver failure had marked pathological damage in liver tissue, as well as significant increases in the levels of ALT, AST, blood ammonia, TNF-α, and IFN-γ (t≥5.367, all P < 0.05). ACY1215 significantly improved the pathological damage in liver tissue and reduced the serum levels of ALT, AST, blood ammonia, TNF-α, and IFN-γ (t≤-3.515, all P < 0.05). ACY1215 also significantly reduced the expression of NF-κB-p65 (t = -5.871, P = 0.004) and the mRNA expression of TNF-α (t = -11.913, P < 0.01) in brain tissue and brain water content (t = -2.355, P < 0.01). According to the results of electron microscopy, the model group had an abnormal blood-brain barrier structure, and the ACY1215 group had slighter damage than the model group. Compared with the normal group, the model group had significant increases in the acetylation level of histone H3 and H4 in brain tissue (t≥3.009, both P < 0.05), while ACY1215 further upregulated the acetylation levels of histone H3 and H4 (t≥6.682, both P < 0.05).@*Conclusion@#ACY1215 exerts a protective effect against brain edema in mice with acute liver failure, possibly by regulating histone acetylation and inhibiting inflammation.

Tetrahydroisoquinolines as novel histone deacetylase inhibitors for treatment of cancer

Histone acetylation is a critical process in the regulation of chromatin structure and gene expression. Histone deacetylases (HDACs) remove the acetyl group, leading to chromatin condensation and transcriptional repression. HDAC inhibitors are considered a new class of anticancer agents and have been shown to alter gene transcription and exert antitumor effects. This paper describes our work on the structural determination and structure-activity relationship (SAR) optimization of tetrahydroisoquinoline compounds as HDAC inhibitors. These compounds were tested for their ability to inhibit HDAC 1, 3, 6 and for their ability to inhibit the proliferation of a panel of cancer cell lines. Among these, compound 82 showed the greatest inhibitory activity toward HDAC 1, 3, 6 and strongly inhibited growth of the cancer cell lines, with results clearly superior to those of the reference compound, vorinostat (SAHA). Compound 82 increased the acetylation of histones H3, H4 and tubulin in a concentration-dependent manner, suggesting that it is a broad inhibitor of HDACs.

Radiosensitization of histone deacetylases inhibitor panobinostat in prostate cancer cells / 中华放射肿瘤学杂志

Objective To study the radiosensitization of histone deaeetylases inhibitor(HDACI) panobinistat in prostate cancer cells in vitro,as well as the possible mechanisms.Methods IC20 of two prostate cancer cell lines(LNCaP and PC-3)was determined using MTI assay.Cells received a single dose irradiation of 0,2,4,6,or 8 Gy using 6 MV X-ray for radiosensitivity experiment,but only 2 Gy for western blot and flow cytometry.Radiosensitization of panobinostat was investigated with clonogenic assay,and sensitizing enhancement ratio(SER)was calculated with single-hit multi-target model.Western blot was used to compare γH2AX expression.Flowcytomctry was used to detect the cell cycle distribution.Results IC20 of LNCaP and PC-3 was 2.5 and 10.0 μmol/L,respectively.SER of panobinostat at IC20 was 1.37(D0 ratio)and 1.11(Dq ratio)for LNCaP cells,and 1.78(D0 ratio)and 1.17(Dq ratio)for PC-3 cells.Expression of γH2AX gradually decreased in the 2 Gy irradiation-alone cells standing for the DSB repair,while γH2AX expression was persistent in the combination group.Irradiation triggered a G2/M arrest 6-12 hours after irradiation in LNCaP and PC-3 cells.G2/M arrest was observed when cells were treated with panobinostat for 24 hours,however,no significant change concerning cell cycle distribution was showed when cells received further irradiation.Conclusions Panobinostat Call radiosensitize prostate cancer cells,which may be related with increased DNA DSB,inhibition of DSB repair and attenuation of cell cycle modulation after irradiation.