The Hepatitis B Virus Ribonuclease H Is Sensitive to Inhibitors of the Human Immunodeficiency Virus Ribonuclease H and Integrase Enzymes

Nucleos(t)ide analog therapy blocks DNA synthesis by the hepatitis B virus (HBV) reverse transcriptase and can control the infection, but treatment is life-long and has high costs and unpredictable long-term side effects. The profound suppression of HBV by the nucleos(t)ide analogs and their ability to cure some patients indicates that they can push HBV to the brink of extinction. Consequently, more patients could be cured by suppressing HBV replication further using a new drug in combination with the nucleos(t)ide analogs. The HBV ribonuclease H (RNAseH) is a logical drug target because it is the second of only two viral enzymes that are essential for viral replication, but it has not been exploited, primarily because it is very difficult to produce active enzyme. To address this difficulty, we expressed HBV genotype D and H RNAseHs in E. coli and enriched the enzymes by nickel-affinity chromatography. HBV RNAseH activity in the enriched lysates was characterized in preparation for drug screening. Twenty-one candidate HBV RNAseH inhibitors were identified using chemical structure-activity analyses based on inhibitors of the HIV RNAseH and integrase. Twelve anti-RNAseH and anti-integrase compounds inhibited the HBV RNAseH at 10 μM, the best compounds had low micromolar IC50 values against the RNAseH, and one compound inhibited HBV replication in tissue culture at 10 μM. Recombinant HBV genotype D RNAseH was more sensitive to inhibition than genotype H. This study demonstrates that recombinant HBV RNAseH suitable for low-throughput antiviral drug screening has been produced. The high percentage of compounds developed against the HIV RNAseH and integrase that were active against the HBV RNAseH indicates that the extensive drug design efforts against these HIV enzymes can guide anti-HBV RNAseH drug discovery. Finally, differential inhibition of HBV genotype D and H RNAseHs indicates that viral genetic variability will be a factor during drug development. © 2013 Tavis et al

Development of a series of 3-hydroxyquinolin-2(1H)-ones as selective inhibitors of HIV-1 reverse transcriptase associated RNase H activity

We report herein the synthesis of a series of 3-hydroxyquinolin-2(1H)-one derivatives. Esters and amide groups were introduced at position 4 of the basis scaffold and some modulations of the benzenic moiety were performed. Most compounds presented selective inhibitory properties in the 10–20 μM range against HIV-1 reverse transcriptase associated ribonuclease H activity, without affecting the integrase and reverse transcriptase DNA polymerase activities. Unfortunately all tested compounds exhibited high cellular cytotoxicity in cell culture which limited their applications as antiviral agents

2‑Hydroxyisoquinoline-1,3(2<i>H</i>,4<i>H</i>)‑diones (HIDs), Novel Inhibitors of HIV Integrase with a High Barrier to Resistance

Clinical HIV-1 integrase (IN) strand transfer inhibitors (INSTIs) potently inhibit viral replication with a dramatic drop in viral load. However, the emergence of resistance to these drugs underscores the need to develop next-generation IN catalytic site inhibitors with improved resistance profiles. Here, we present a novel candidate IN inhibitor, MB-76, a 2-hydroxyisoquinoline-1,3­(2<i>H</i>,4<i>H</i>)-dione (HID) derivative. MB-76 potently blocks HIV integration and is active against a panel of wild-type as well as raltegravir-resistant HIV-1 variants. The lack of cross-resistance with other INSTIs and the absence of resistance selection in cell culture indicate the potential of HID derivatives compared to previous INSTIs. A crystal structure of MB-76 bound to the wild-type prototype foamy virus intasome reveals an overall binding mode similar to that of INSTIs. Its compact scaffold displays all three Mg²⁺ chelating oxygen atoms from a single ring, ensuring that the only direct contacts with IN are the invariant P214 and Q215 residues of PFV IN (P145 and Q146 for HIV-1 IN, respectively), which may partially explain the difficulty of selecting replicating resistant variants. Moreover, the extended, dolutegravir-like linker connecting the MB-76 metal chelating core and <i>p</i>-fluorobenzyl group can provide additional flexibility in the perturbed active sites of raltegravir-resistant INs. The compound identified represents a potential candidate for further (pre)­clinical development as next-generation HIV IN catalytic site inhibitor

Salvage radiotherapy with or without short-term hormone therapy for rising prostate-specific antigen concentration after radical prostatectomy (GETUG-AFU 16): a randomised, multicentre, open-label phase 3 trial

International audienceBACKGROUND: How best to treat rising prostate-specific antigen (PSA) concentration after radical prostatectomy is an urgent clinical question. Salvage radiotherapy delays the need for more aggressive treatment such as long-term androgen suppression, but fewer than half of patients benefit from it. We aimed to establish the effect of adding short-term androgen suppression at the time of salvage radiotherapy on biochemical outcome and overall survival in men with rising PSA following radical prostatectomy. METHODS: This open-label, multicentre, phase 3, randomised controlled trial, was done in 43 French study centres. We enrolled men (aged \textgreater/=18 years) who had received previous treatment for a histologically confirmed adenocarcinoma of the prostate (but no previous androgen deprivation therapy or pelvic radiotherapy), and who had stage pT2, pT3, or pT4a (bladder neck involvement only) in patients who had rising PSA of 0.2 to less than 2.0 mug/L following radical prostatectomy, without evidence of clinical disease. Patients were randomly assigned (1:1) centrally via an interactive web response system to standard salvage radiotherapy (three-dimensional [3D] conformal radiotherapy or intensity modulated radiotherapy, of 66 Gy in 33 fractions 5 days a week for 7 weeks) or radiotherapy plus short-term androgen suppression using 10.8 mg goserelin by subcutaneous injection on the first day of irradiation and 3 months later. Randomisation was stratified using a permuted block method according to investigational site, radiotherapy modality, and prognosis. The primary endpoint was progression-free survival, analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT00423475. FINDINGS: Between Oct 19, 2006, and March 30, 2010, 743 patients were randomly assigned, 374 to radiotherapy alone and 369 to radiotherapy plus goserelin. Patients assigned to radiotherapy plus goserelin were significantly more likely than patients in the radiotherapy alone group to be free of biochemical progression or clinical progression at 5 years (80% [95% CI 75-84] vs 62% [57-67]; hazard ratio [HR] 0.50, 95% CI 0.38-0.66; p\textless0.0001). No additional late adverse events occurred in patients receiving short-term androgen suppression compared with those who received radiotherapy alone. The most frequently occuring acute adverse events related to goserelin were hot flushes, sweating, or both (30 [8%] of 366 patients had a grade 2 or worse event; 30 patients [8%] had hot flushes and five patients [1%] had sweating in the radiotherapy plus goserelin group vs none of 372 patients in the radiotherapy alone group). Three (8%) of 366 patients had grade 3 or worse hot flushes and one patient had grade 3 or worse sweating in the radiotherapy plus goserelin group versus none of 372 patients in the radiotherapy alone group. The most common late adverse events of grade 3 or worse were genitourinary events (29 [8%] in the radiotherapy alone group vs 26 [7%] in the radiotherapy plus goserelin group) and sexual disorders (20 [5%] vs 30 [8%]). No treatment-related deaths occurred. INTERPRETATION: Adding short-term androgen suppression to salvage radiotherapy benefits men who have had radical prostatectomy and whose PSA rises after a postsurgical period when it is undetectable. Radiotherapy combined with short-term androgen suppression could be considered as a reasonable option in this population. FUNDING: French Ministry of Health, AstraZeneca, and La Ligue Contre le Cance

Haploinsufficiency for NR3C1, the gene encoding the glucocorticoid receptor, in blastic plasmacytoid dendritic cell neoplasms

International audienceBlastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and highly aggressiveleukemia for which knowledge on disease mechanisms and effective therapies are currentlylacking. Only a handful of recurring genetic mutations have been identified and none isspecific to BPDCN. In this study, through molecular cloning in an index case that presenteda balanced t(3;5)(q21;q31) and molecular cytogenetic analyses in a further 46 cases, weidentify monoallelic deletion of NR3C1 (5q31), encoding the glucocorticoid receptor (GCR),in 13 of 47 (28%) BPDCN patients. Targeted deep sequencing in 36 BPDCN cases, including10 with NR3C1 deletion, did not reveal NR3C1 point mutations or indels. Haploinsufficiencyfor NR3C1 defined a subset of BPDCN with lowered GCR expression and extremely pooroverall survival (P 5 .0006). Consistent with a role for GCR in tumor suppression, functionalanalyses coupled with gene expression profiling identified corticoresistance and loss-ofEZH2 function as major downstream consequences of NR3C1 deletion in BPDCN.Subsequently, more detailed analyses of the t(3;5)(q21;q31) revealed fusion of NR3C1 to along noncoding RNA (lncRNA) gene (lincRNA-3q) that encodes a novel, nuclear, noncodingRNA involved in the regulation of leukemia stem cell programs and G1/S transition, via E2F.Overexpression oflincRNA-3qwas a consistent feature ofmalignant cells and could be abrogated by bromodomain and extraterminal domain(BET) protein inhibition. Taken together, this work points to NR3C1 as a haploinsufficient tumor suppressor in a subset of BPDCN andidentifies BET inhibition, acting at least partially via lncRNA blockade, as a novel treatment option in BPDCN.