Cohort profile: PRESTIGIO, an Italian prospective registry-based cohort of people with HIV-1 resistant to reverse transcriptase, protease and integrase inhibitors.

PURPOSE: The PRESTIGIO Registry was established in 2017 to collect clinical, virological and immunological monitoring data from people living with HIV (PLWH) with documented four-class drug resistance (4DR). Key research purposes include the evaluation of residual susceptibility to specific antiretrovirals and the validation of treatment and monitoring strategies in this population. PARTICIPANTS: The PRESTIGIO Registry collects annual plasma and peripheral blood mononuclear cell samples and demographic, clinical, virological, treatment and laboratory data from PLWH followed at 39 Italian clinical centres and characterised by intermediate-to-high genotypic resistance to ≥1 nucleoside reverse transcriptase inhibitors, ≥1 non-nucleoside reverse transcriptase inhibitors, ≥1 protease inhibitors, plus either intermediate-to-high genotypic resistance to ≥1 integrase strand transfer inhibitors (INSTIs) or history of virological failure to an INSTI-containing regimen. To date, 229 people have been recorded in the cohort. Most of the data are collected from the date of the first evidence of 4DR (baseline), with some prebaseline information obtained retrospectively. Samples are collected from the date of enrollment in the registry. FINDINGS TO DATE: The open-ended cohort has been used to assess (1) prognosis in terms of survival or development of AIDS-related or non-AIDS-related clinical events; (2) long-term efficacy and safety of different antiretroviral regimens and (3) virological and immunological factors predictive of clinical outcome and treatment efficacy, especially through analysis of plasma and cell samples. FUTURE PLANS: The registry can provide new knowledge on how to implement an integrated approach to study PLWH with documented resistance to the four main antiretroviral classes, a population with a limited number of individuals characterised by a high degree of frailty and complexity in therapeutic management. Given the scheduled annual updates of PLWH data, the researchers who collaborate in the registry can send study proposals at any time to the steering committee of the registry, which evaluates every 3 months whether the research studies can be conducted on data and biosamples from the registry and whether they are aimed at a better understanding of a specific health condition, the emergence of comorbidities or the effect of potential treatments or experimental drugs that may have an impact on disease progression and quality of life. Finally, the research studies should aim to be inclusive, innovative and in touch with the communities and society as a whole. TRIAL REGISTRATION NUMBER: NCT04098315.

CD8+ T cells control SIV infection using both cytolytic effects and non-cytolytic suppression of virus production.

Whether CD8+ T lymphocytes control human immunodeficiency virus infection by cytopathic or non-cytopathic mechanisms is not fully understood. Multiple studies highlighted non-cytopathic effects, but one hypothesis is that cytopathic effects of CD8+ T cells occur before viral production. Here, to examine the role of CD8+ T cells prior to virus production, we treated SIVmac251-infected macaques with an integrase inhibitor combined with a CD8-depleting antibody, or with either reagent alone. We analyzed the ensuing viral dynamics using a mathematical model that included infected cells pre- and post- viral DNA integration to compare different immune effector mechanisms. Macaques receiving the integrase inhibitor alone experienced greater viral load decays, reaching lower nadirs on treatment, than those treated also with the CD8-depleting antibody. Models including CD8+ cell-mediated reduction of viral production (non-cytolytic) were found to best explain the viral profiles across all macaques, in addition an effect in killing infected cells pre-integration (cytolytic) was supported in some of the best models. Our results suggest that CD8+ T cells have both a cytolytic effect on infected cells before viral integration, and a direct, non-cytolytic effect by suppressing viral production.

HIV-1 integrase inhibitor raltegravir promotes DNA damage-induced apoptosis in multiple myeloma.

Raltegravir, the first integrase inhibitor approved for the treatment of HIV infection, has been implicated as a promising potential in cancer treatment. Therefore, the present study aimed to investigate the repurposing of raltegravir as an anticancer agent and its mechanism of action in multiple myeloma (MM). Human MM cell lines (RPMI-8226, NCI H929, and U266) and normal peripheral blood mononuclear cells (PBMCs) were cultured with different concentrations of raltegravir for 48 and 72 h. Cell viability and apoptosis were then measured by MTT and Annexin V/PI assays, respectively. Protein levels of cleaved PARP, Bcl-2, Beclin-1, and phosphorylation of histone H2AX were detected by Western blotting. In addition, the mRNA levels of V(D)J recombination and DNA repair genes were analyzed using qPCR. Raltegravir treatment for 72 h significantly decreased cell viability, increased apoptosis, and DNA damage in MM cells while having minimum toxicity on cell viability of normal PBMCs approximately from 200 nM (0.2 µM; p < .01 for U66 and p < .0001 for NCI H929 and RPMI 8226 cells). Furthermore, raltegravir treatment altered the mRNA levels of V(D)J recombination and DNA repair genes. We report for the first time that treatment with raltegravir is associated with decreased cell viability, apoptosis induction, DNA damage accumulation, and alteration of mRNA expression of genes involved in V(D)J recombination and DNA repair in MM cell lines, all of which show its potential for anti-myeloma effects. Hence, raltegravir may significantly impact the treatment of MM, and further studies are required to confirm its efficacy and mechanism of action in more detail in patient-derived myeloma cells and in-vivo models.

[Genetic Subtypes and Status of Transmitted Drug Resistance of HIV/AIDS Patients in Sichuan].

Objective: To investigate the distribution characteristics of the HIV genetic subtypes and the status quo of transmitted drug resistance among HIV/AIDS patients in Sichuan with no previous history of receiving antiretroviral therapy (ART). Methods: Adult HIV/AIDS patients who were hospitalized in Sichuan and who had no previous history of exposure to ART drugs exposure were enrolled. In-house sequencing of the HIV gene was done and phylogenetic tree was constructed to analyze the HIV genetic subtypes. The Stanford HIV drug resistance database was used to make online comparison of the drug resistance mutation sites and to determine the presence or absence of drug resistance, and the type and level of drug resistance. Results: A total of 120 patients were enrolled for the study, and 120 blood samples were collected. The genetic subtypes of 87.5% (105/120) of the samples were successfully amplified. The distribution characteristics of HIV genotype were as follows, CRF01_AE accounted for 46.67% (49/105), CRF07_BC accounted for 39.05% (41/105), and the others genetic subtypes, 14.28% (15/105). There were no significant differences between the different genetic subtypes in sex, age, ethnicity, HIV transmission route, drug resistance, baseline HIV RNA and baseline CD4 ( P>0.05). Drug-resistant mutation sites were detected in 25 samples, accounting for 20.83% (25/120) of all samples, with 16.67% (20/120) being potential drug resistance and 4.17% (5/120) being transmitted drug resistance. For the 24 samples found to be resistant to non-nucleoside reverse transcriptase inhibitors (NNRTIs), the mutation frequency of V179D/E was the highest. One patient showed resistance to protease inhibitors (PI) and the mutation site was M46I. No nucleoside reverse transcriptase inhibitor (NRTI) or integrase inhibitors (INTI) resistance were found. Conclusions: The main genetic subtypes of HIV/AIDS patients in Sichuan with no previous history of receiving ART were CRF01_AE and CRF07_BC. The incidence of transmitted drug resistance was low. The drug resistance detected in the study was predominantly resistance to NNRTIs. Baseline HIV drug resistance testing is of great significance for formulating effective ART regimens.

Use of integrase inhibitors in HIV-associated tuberculosis in high-burden settings: implementation challenges and research gaps.

People living with HIV have a higher risk of developing tuberculosis, and tuberculosis is one of the leading causes of death among people living with HIV globally. Treating HIV and tuberculosis concurrently has morbidity and mortality benefits. However, HIV and tuberculosis co-treatment is challenging due to drug-drug interactions, overlapping toxicities, tuberculosis-associated immune reconstitution syndrome, and concerns for treatment failure or drug resistance. Drug-drug interactions between antiretrovirals and tuberculosis drugs are driven mainly by the rifamycins (for example, the first-line tuberculosis drug rifampicin), and dose adjustments or drug switches during co-treatment are commonly required. Several implementation challenges and research gaps exist when combining the integrase strand transfer inhibitors (INSTIs), highly potent antiretroviral drugs recommended as first-line treatment of HIV, and drugs used for the treatment and prevention of tuberculosis. Ongoing and planned studies will address some critical questions on the use of INSTIs in settings with a high tuberculosis burden, including dosing of dolutegravir, bictegravir, and cabotegravir when used with the rifamycins for both tuberculosis treatment and prevention. Failure, in the past, to include people with tuberculosis in HIV clinical treatment trials has been responsible for some of the research gaps still evident for informing optimisation of HIV and tuberculosis co-treatment.

Clinical trial of raltegravir, an integrase inhibitor, in HAM/TSP.

OBJECTIVE: Human T-cell lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive myelopathy. A high proviral load (PVL) is one of the main risk factors for HAM/TSP. Recently, it was shown that raltegravir could inhibit cell-free and cell-to-cell transmission of HTLV-1 in vitro. Given the substantial clinical experience in human immunodeficiency virus infection and its excellent safety profile, this agent may be an attractive therapeutic option for HAM/TSP patients. METHODS: Sixteen subjects with HAM/TSP received raltegravir 400 mg orally twice daily in an initial 6-month treatment phase, followed by a 9-month post-treatment phase. HTLV-1 PVLs were assessed using droplet digital PCR from the PBMCs every 3 months, and from the CSF at baseline, month 6, and month 15. We also evaluated the ability of raltegravir to regulate abnormal immune responses in HAM/TSP patients. RESULTS: While a downward trend was observed in PBMC and/or CSF PVLs of some patients, raltegravir overall did not have any impact on the PVL in this HAM/TSP patient cohort. Clinically, all patients' neurological scores and objective measurements remained relatively stable, with some expected variability. Immunologic studies showed alterations in the immune profiles of a subset of patients including decreased CD4+ CD25+ T cells and spontaneous lymphoproliferation. INTERPRETATION: Raltegravir was generally well tolerated in this HAM/TSP patient cohort. A subset of patients exhibited a mild decrease in PVL as well as variations in their immune profiles after taking raltegravir. These findings suggest that raltegravir may be a therapeutic option in select HAM/TSP patients. CLINICAL TRIAL REGISTRATION NUMBER: NCT01867320.

Cryo-EM structure of the Rous sarcoma virus octameric cleaved synaptic complex intasome.

Despite conserved catalytic integration mechanisms, retroviral intasomes composed of integrase (IN) and viral DNA possess diverse structures with variable numbers of IN subunits. To investigate intasome assembly mechanisms, we employed the Rous sarcoma virus (RSV) IN dimer that assembles a precursor tetrameric structure in transit to the mature octameric intasome. We determined the structure of RSV octameric intasome stabilized by a HIV-1 IN strand transfer inhibitor using single particle cryo-electron microscopy. The structure revealed significant flexibility of the two non-catalytic distal IN dimers along with previously unrecognized movement of the conserved intasome core, suggesting ordered conformational transitions between intermediates that may be important to capture the target DNA. Single amino acid substitutions within the IN C-terminal domain affected intasome assembly and function in vitro and infectivity of pseudotyped RSV virions. Unexpectedly, 17 C-terminal amino acids of IN were dispensable for virus infection despite regulating the transition of the tetrameric intasome to the octameric form in vitro. We speculate that this region may regulate the binding of highly flexible distal IN dimers to the intasome core to form the octameric complex. Our studies reveal key steps in the assembly of RSV intasomes.

Investigation of drug resistance against protease, reverse transcriptase, and integrase inhibitors by next-generation sequencing in HIV-positive patients.

Our aim was to investigate the mutations in protease (PR), reverse transcriptase (RT), and integrase (IN) gene regions in human immunodeficiency virus (HIV) using a single amplicon via next-generation sequencing (NGS). The study included plasma samples from 49 HIV-1-positive patients, which were referred for HIV-1 drug resistance testing during 2017. A nested polymerase chain reaction (PCR) was performed after the RNA extraction and one-step reverse transcription stages. The sequencing of the HIV genome in the PR, RT, and IN gene regions was carried out using MiSeq NGS technology. Sanger sequencing (SS) was used to analyze resistance mutations in the PR and RT gene regions using a ViroSeq HIV-1 Genotyping System. PCR products were analyzed with an ABI3500 GeneticAnalyzer (Applied Biosystems). Resistance mutations detected with NGS at frequencies above 20% were identical to the SS results. Resistance to at least one antiretroviral (ARV) drug was 22.4% (11 of 49) with NGS and 10.2% (5 of 49) with SS. At least one low-frequency resistance mutation was detected in 18.3% (9 of 49) of the samples. Low-frequency resistance mutations resulted in virological failure in only one patient. The cost of the analyses was reduced by sample pooling and multiplex analysis using the MiSeq system. This is the first study in Turkey to use NGS technologies for the detection of resistance mutations in all three gene (PR, RT, IN) regions using a single amplicon. Our findings suggest that NGS is more sensitive and cost-effective than the SS method.

Integrase inhibitor-based antiretroviral treatments decrease oxidative stress caused by HIV infection.

OBJECTIVE: Several chronic illnesses, including HIV infection are associated with oxidative stress. In addition to HIV itself, some antiretrovirals also increase oxidative stress while decreasing viral replication. To investigate the alterations in oxidative stress parameters and thiol-disulphide homeostasis in people living with HIV who were receiving integrase inhibitor-based antiretroviral therapy. PATIENTS AND METHODS: Thirty treatment-naive adult people living with HIV were prospectively enrolled in the study. Sera were collected from patients twice: at the beginning of antiretroviral therapy (group 1) and 6 months later (group 2). Thirty age-matched healthy volunteers were enrolled in the study as the control group (group 3). Serum levels of total antioxidant status (TAS) and total oxidative status (TOS) were determined using an automated measurement method. Serum malondialdehyde (MDA) and protein carbonyl (PC) levels were measured spectrophotometrically. CD4+ T-cells were counted flow cytometrically. A mathematical equation was used to calculate the oxidative stress index (OSI) and determine disulfide levels (DIS). RESULTS: TOS, OSI, MDA, and PC levels were significantly increased in treatment-naive people living with HIV than in those receiving ART (p<0.001). Total and native thiol were significantly lower in both HIV-infected groups than in the control group (p<0.001). PC and MDA levels were significantly higher in both HIV-infected groups than in the control group (p<0.001). In correlation analysis, MDA and age were negatively correlated, whereas TAS was positively correlated with CD4+ T-cell count in treatment-naive people living with HIV. Age was positively correlated with TOS (r:0.421, p:0.023) in healthy controls. CONCLUSIONS: Integrase inhibitor-based antiretroviral treatments decrease the oxidative stress caused by HIV infection and may be a good therapeutic option in people living with HIV.

De novo design based identification of potential HIV-1 integrase inhibitors: A pharmacoinformatics study.

In the present study, pharmacoinformatics paradigms include receptor-based de novo design, virtual screening through molecular docking and molecular dynamics (MD) simulation are implemented to identify novel and promising HIV-1 integrase inhibitors. The de novodrug/ligand/molecule design is a powerful and effective approach to design a large number of novel and structurally diverse compounds with the required pharmacological profiles. A crystal structure of HIV-1 integrase bound with standard inhibitor BI-224436 is used and a set of 80,000 compounds through the de novo approach in LigBuilder is designed. Initially, a number of criteria including molecular docking, in-silico toxicity and pharmacokinetics profile assessments are implied to reduce the chemical space. Finally, four de novo designed molecules are proposed as potential HIV-1 integrase inhibitors based on comparative analyses. Notably, strong binding interactions have been identified between a few newly identified catalytic amino acid residues and proposed HIV-1 integrase inhibitors. For evaluation of the dynamic stability of the protein-ligand complexes, a number of parameters are explored from the 100 ns MD simulation study. The MD simulation study suggested that proposed molecules efficiently retained their molecular interaction and structural integrity inside the HIV-1 integrase. The binding free energy is calculated through the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) approach for all complexes and it also explains their thermodynamic stability. Hence, proposed molecules through de novo design might be critical to inhibiting the HIV-1 integrase.

An Elvitegravir Nanoformulation Crosses the Blood-Brain Barrier and Suppresses HIV-1 Replication in Microglia.

Even with an efficient combination of antiretroviral therapy (ART), which significantly decreases viral load in human immunodeficiency virus type 1 (HIV-1)-positive individuals, the occurrence of HIV-1-associated neurocognitive disorders (HAND) still exists. Microglia have been shown to have a significant role in HIV-1 replication in the brain and in subsequent HAND pathogenesis. However, due to the limited ability of ART drugs to cross the blood-brain barrier (BBB) after systemic administration, in addition to efflux transporter expression on microglia, the efficacy of ART drugs for viral suppression in microglia is suboptimal. Previously, we developed novel poly (lactic-co-glycolic acid) (PLGA)-based elvitegravir nanoparticles (PLGA-EVG NPs), which showed improved BBB penetration in vitro and improved viral suppression in HIV-1-infected primary macrophages, after crossing an in vitro BBB model. Our objective in the current study was to evaluate the efficacy of our PLGA-EVG NPs in an important central nervous system (CNS) HIV-1 reservoir, i.e., microglia. In this study, we evaluated the cyto-compatibility of the PLGA-EVG NPs in microglia, using an XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay and cellular morphology observation. We also studied the endocytosis pathway and the subcellular localization of PLGA NPs in microglia, using various endocytosis inhibitors and subcellular localization markers. We determined the ability of PLGA-EVG NPs to suppress HIV-1 replication in microglia, after crossing an in vitro BBB model. We also studied the drug levels in mouse plasma and brain tissue, using immunodeficient NOD scid gamma (NSG) mice, and performed a pilot study, to evaluate the efficacy of PLGA-EVG NPs on viral suppression in the CNS, using an HIV-1 encephalitic (HIVE) mouse model. From our results, the PLGA-EVG NPs showed ~100% biocompatibility with microglia, as compared to control cells. The internalization of PLGA NPs in microglia occurred through caveolae-/clathrin-mediated endocytosis. PLGA NPs can also escape from endo-lysosomal compartments and deliver the therapeutics to cells efficiently. More importantly, the PLGA-EVG NPs were able to show ~25% more viral suppression in HIV-1-infected human-monocyte-derived microglia-like cells after crossing the in vitro BBB compared to the EVG native drug, without altering BBB integrity. PLGA-EVG NPs also showed a ~two-fold higher level in mouse brain and a trend of decreasing CNS HIV-1 viral load in HIV-1-infected mice. Overall, these results help us to create a safe and efficient drug delivery method to target HIV-1 reservoirs in the CNS, for potential clinical use.

HIV­1 integrase inhibitors targeting various DDE transposases: Retroviral integration versus RAG­mediated recombination (Review).

Transposases are ubiquitous mobile genetic elements responsible for genome development, driving rearrangements, such as insertions, deletions and translocations. Across species evolution, some transposases are tamed by their host and are made part of complex cellular systems. The proliferation of retroviruses is also dependent on transposase related enzymes termed integrases. Recombination­activating gene protein (RAG)1 and metnase are just two examples of transposase domestication and together with retroviral integrases (INs), they belong to the DDE polynucleotidyl transferases superfamily. They share mechanistic and structural features linked to the RNase H­like fold, harboring a DDE(D) metal dependent catalytic motif. Recent antiretroviral compounds target the catalytic domain of integrase, but they also have the potential of inhibiting other related enzymes. In this review, we report the activity of different classes of integrase inhibitors on various DDE transposases. Computational simulations are useful to predict the extent of off­target activity and have been employed to study the interactions between RAG1 recombinase and compounds from three different pharmacologic classes. We demonstrate that strand­transfer inhibitors display a higher affinity towards the RAG1 RNase H domain, as suggested by experimental data compared to allosteric inhibitors. While interference with RAG1 and 2 recombination is associated with a negative impact on immune function, the inhibition of metnase or HTLV­1 integrase opens the way for the development of novel therapies for refractory cancers.

Structural Insights on Retroviral DNA Integration: Learning from Foamy Viruses.

Foamy viruses (FV) are retroviruses belonging to the Spumaretrovirinae subfamily. They are non-pathogenic viruses endemic in several mammalian hosts like non-human primates, felines, bovines, and equines. Retroviral DNA integration is a mandatory step and constitutes a prime target for antiretroviral therapy. This activity, conserved among retroviruses and long terminal repeat (LTR) retrotransposons, involves a viral nucleoprotein complex called intasome. In the last decade, a plethora of structural insights on retroviral DNA integration arose from the study of FV. Here, we review the biochemistry and the structural features of the FV integration apparatus and will also discuss the mechanism of action of strand transfer inhibitors.

Brief Report: Efficacy and Safety of Switching to Coformulated Elvitegravir, Cobicistat, Emtricitabine, and Tenofovir Alafenamide (E/C/F/TAF) in Virologically Suppressed Women.

BACKGROUND: The integrase inhibitor regimen [elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (TDF)] demonstrated superior efficacy when compared with a protease inhibitor regimen [ritonavir-boosted atazanavir (ATV + RTV) and FTC/TDF] in 575 treatment-naive women at week 48. We investigated the efficacy, safety, and tolerability of switching to a TAF-based, single-tablet regimen containing elvitegravir, cobicistat, FTC, and tenofovir alafenamide (E/C/F/TAF) versus remaining on ATV + RTV plus FTC/TDF. METHODS: After completing the initial randomized, blinded phase, virologically suppressed (HIV-1 RNA <50 copies/mL) women on ATV + RTV plus FTC/TDF were rerandomized (3:1) to receive open-label E/C/F/TAF versus remaining on their current regimen. The primary end point was proportion of participants with plasma HIV-1 RNA <50 copies per milliliter at week 48 (U.S. FDA snapshot algorithm), with a prespecified noninferiority margin of 12%. Safety [adverse events (AEs)] and tolerability were also assessed. RESULTS: Of 575 women originally randomized and treated in the blinded phase, 159 were rerandomized to switch to E/C/F/TAF and 53 to remain on ATV + RTV plus FTC/TDF. At week 48, virologic suppression was maintained in 150 (94%) of women on E/C/F/TAF and 46 (87%) on ATV + RTV plus FTC/TDF [difference 7.5% (95% confidence interval -1.2% to 19.4%)], demonstrating noninferiority of E/C/F/TAF to ATV + RTV and FTC/TDF. Incidence of AEs was similar between groups; study drug-related AEs were more common with E/C/F/TAF (11% versus 4%). CONCLUSIONS: Switching to E/C/F/TAF was noninferior to continuing ATV + RTV plus FTC/TDF in maintaining virologic suppression and was well tolerated at 48 weeks.

Quinoline, Coumarin and Other Heterocyclic Analogs Based HIV-1 Integrase Inhibitors.

Human Immunodeficiency Virus Type 1 Integrase or HIV-1 integrase (IN) is a 288 amino acid protein that incorporates the retrotranscribed viral DNA into the host chromosomal DNA. Over the past 30 years, large number of derivatives have been evaluated for their inhibitory potential against IN. There is vast literature available which need to be collated to help scientists plan the future drug design. This review discusses the reports of past 25 years on analogs of quinoline, coumarin and other related heterocycles, which exhibit low micromolar inhibitory potency against IN.

Susceptibility of Human Endogenous Retrovirus Type K to Reverse Transcriptase Inhibitors.

Human endogenous retroviruses (HERVs) make up 8% of the human genome. The HERV type K (HERV-K) HML-2 (HK2) family contains proviruses that are the most recent entrants into the human germ line and are transcriptionally active. In HIV-1 infection and cancer, HK2 genes produce retroviral particles that appear to be infectious, yet the replication capacity of these viruses and potential pathogenicity has been difficult to ascertain. In this report, we screened the efficacy of commercially available reverse transcriptase inhibitors (RTIs) at inhibiting the enzymatic activity of HK2 RT and HK2 genomic replication. Interestingly, only one provirus, K103, was found to encode a functional RT among those examined. Several nucleoside analogue RTIs (NRTIs) blocked K103 RT activity and consistently inhibited the replication of HK2 genomes. The NRTIs zidovudine (AZT), stavudine (d4T), didanosine (ddI), and lamivudine (3TC), and the nucleotide RTI inhibitor tenofovir (TDF), show efficacy in blocking K103 RT. HIV-1-specific nonnucleoside RTIs (NNRTIs), protease inhibitors (PIs), and integrase inhibitors (IIs) did not affect HK2, except for the NNRTI etravirine (ETV). The inhibition of HK2 infectivity by NRTIs appears to take place at either the reverse transcription step of the viral genome prior to HK2 viral particle formation and/or in the infected cells. Inhibition of HK2 by these drugs will be useful in suppressing HK2 infectivity if these viruses prove to be pathogenic in cancer, neurological disorders, or other diseases associated with HK2. The present studies also elucidate a key aspect of the life cycle of HK2, specifically addressing how they do, and/or did, replicate.IMPORTANCE Endogenous retroviruses are relics of ancestral virus infections in the human genome. The most recent of these infections was caused by HK2. While HK2 often remains silent in the genome, this group of viruses is activated in HIV-1-infected and cancer cells. Recent evidence suggests that these viruses are infectious, and the potential exists for HK2 to contribute to disease. We show that HK2, and specifically the enzyme that mediates virus replication, can be inhibited by a panel of drugs that are commercially available. We show that several drugs block HK2 with different efficacies. The inhibition of HK2 replication by antiretroviral drugs appears to occur in the virus itself as well as after infection of cells. Therefore, these drugs might prove to be an effective treatment by suppressing HK2 infectivity in diseases where these viruses have been implicated, such as cancer and neurological syndromes.

Analysis of transmitted HIV drug resistance from 2005 to 2015 in Victoria, Australia: a comparison of the old and the new.

Background Baseline genotyping is part of standard-of-care treatment. It reveals that transmitted drug resistance (TDR) continues to be important for the management of HIV infection. Attention is typically focused on determining whether resistance to the protease inhibitors (PI) and reverse transcriptase inhibitors (RTI) occurs. However, the increasing use of integrase inhibitors (INIs) raises a concern that TDR to this class of antiretroviral drug may also occur. METHODS: PI and RTI drug resistance genotyping was performed on blood samples collected between 2005 and 2015 from 772 treatment-naïve Victorian patients infected with HIV within the previous 12 months. Integrase genotyping was performed on 461 of the 485 patient samples collected between 2010 and 2015. RESULTS: In the period 2005-10, 39 of 343 patients (11.4%) had at least one PI- or RTI-associated mutation, compared with 34 of 429 (7.9%) during the period 2011-15. Compared with 2005-10, during 2011-15 there was a significant decline in the prevalence of the non-nucleoside-associated mutation K103N and the nucleoside-associated mutations at codons M41 and T215. One patient was detected with a major INI resistance mutation, namely G118R. However, this mutation is rare and its effect on susceptibility is unclear. A small number of patients (n=12) was infected with HIV containing accessory resistance mutations in the integrase gene. CONCLUSIONS: The lack of transmitted resistance to INIs is consistent with a low level of resistance to this class of drugs in the treated population. However, continued surveillance in the newly infected population is warranted as the use of INIs increases.

Prevalence of integrase inhibitor resistance mutations in Austrian patients recently diagnosed with HIV from 2008 to 2013.

PURPOSE: Treatment guidelines often do not advocate testing for integrase inhibitor resistance associated mutations (IRAM) before initiation of first line ART given the extremely low prevalence of mutations found in older surveillance studies. We aimed to describe the prevalence of IRAM in Austrian patients recently diagnosed with HIV in the 5 years following introduction of integrase inhibitors and to analyse trends and factors associated with their detection. METHODS: Samples of antiretroviral treatment (ART) naïve patients recently diagnosed with HIV in Austria between 2008 and 2013 were analysed for the existence of IRAM and drug penalty scores were calculated to estimate response to drugs. Demographic and virological data were extracted from a database. Descriptive and comparative statistics were used. RESULTS: A total of 303 samples were analysed. 78 % were male and mean age was 38 years. Overall prevalence of IRAM was 2.3 %. Six percent had at least potentially low-level resistance to raltegravir or elvitegravir, versus 1 % for dolutegravir. One primary mutation was observed (F121Y) in a patient sample from 2012 leading to 5-10-fold reduced susceptibility to raltegravir and elvitegravir. Two patients carried the accessory mutations E138K and G140A, respectively, where both lie on the Q148 pathway. No temporal trend of IRAM prevalence was observed (p = 0.16). DISCUSSION: Primary IRAM are still rarely found despite the increasing use of INSTI in Austria, but there is a potential for reduced susceptibility to these drugs in selected patients. Routine resistance testing seems prudent to avoid the consequences including accumulation of further mutations and therapeutic failure.