Phase I/II trial of the anti-HIV activity of mifepristone in HIV-infected subjects ACTG 5200

Oncoviruses: How do they hijack their host and current treatment regimes

Viruses have the ability to modulate the cellular machinery of their host to ensure their survival. While humans encounter numerous viruses daily, only a select few can lead to disease progression. Some of these viruses can amplify cancer-related traits, particularly when coupled with factors like immunosuppression and co-carcinogens. The global burden of cancer development resulting from viral infections is approximately 12%, and it arises as an unfortunate consequence of persistent infections that cause chronic inflammation, genomic instability from viral genome integration, and dysregulation of tumor suppressor genes and host oncogenes involved in normal cell growth. This review provides an in-depth discussion of oncoviruses and their strategies for hijacking the host's cellular machinery to induce cancer. It delves into how viral oncogenes drive tumorigenesis by targeting key cell signaling pathways. Additionally, the review discusses current therapeutic approaches that have been approved or are undergoing clinical trials to combat malignancies induced by oncoviruses. Understanding the intricate interactions between viruses and host cells can lead to the development of more effective treatments for virus-induced cancers.

Antivirals that target the host IMPα/β1-virus interface

Although transport into the nucleus mediated by the importin (IMP) α/β1-heterodimer is central to viral infection, small molecule inhibitors of IMPα/β1-dependent nuclear import have only been described and shown to have antiviral activity in the last decade. Their robust antiviral activity is due to the strong reliance of many different viruses, including RNA viruses such as human immunodeficiency virus-1 (HIV-1), dengue (DENV), and Zika (ZIKV), on the IMPα/β1-virus interface. High-throughput compound screens have identified many agents that specifically target this interface. Of these, agents targeting IMPα/β1 directly include the FDA-approved macrocyclic lactone ivermectin, which has documented broad-spectrum activity against a whole range of viruses, including HIV-1, DENV1-4, ZIKV, West Nile virus (WNV), Venezuelan equine encephalitis virus, chikungunya, and most recently, SARS-CoV-2 (COVID-19). Ivermectin has thus far been tested in Phase III human clinical trials for DENV, while there are currently close to 80 trials in progress worldwide for SARS-CoV-2; preliminary results for randomised clinical trials (RCTs) as well as observational/retrospective studies are consistent with ivermectin affording clinical benefit. Agents that target the viral component of the IMPα/β1-virus interface include N-(4-hydroxyphenyl) retinamide (4-HPR), which specifically targets DENV/ZIKV/WNV non-structural protein 5 (NS5). 4-HPR has been shown to be a potent inhibitor of infection by DENV1-4, including in an antibody-dependent enhanced animal challenge model, as well as ZIKV, with Phase II clinical challenge trials planned. The results from rigorous RCTs will help determine the therapeutic potential of the IMPα/β1-virus interface as a target for antiviral development.

Inhibitors of nuclear transport

Central to eukaryotic cell function, transport into and out of the nucleus is largely mediated by members of the Importin (IMP) superfamily of transporters of α- and β-types. The first inhibitor of nuclear transport, leptomycin B (LMB), was shown to be a specific inhibitor of the IMPβ homologue Exportin 1 (EXP1) almost 20 years ago, but it has only been in the last five or so years that new inhibitors of nuclear export as well as import have been identified and characterised. Of utility in biological research, these inhibitors include those that target-specific EXPs/IMPs, with accompanying toxicity profiles, as well as agents that specifically target particular nuclear import cargoes. Both types of inhibitors have begun to be tested in preclinical/clinical studies, with particular focus on limiting various types of cancer or treating viral infection, and the most advanced agent targeting EXP1 (Selinexor) has progressed successfully through >40 clinical trials for a range of high-grade cancers and is approaching FDA approval for a number of indications. Selectively inhibiting the nucleocytoplasmic trafficking of specific proteins of interest remains a challenge, but progress in the area of the host-pathogen interface holds promise for the future.

Novel RU486 (mifepristone) analogues with increased activity against Venezuelan Equine Encephalitis Virus but reduced progesterone receptor antagonistic activity

There are currently no therapeutics to treat infection with the alphavirus Venezuelan equine encephalitis virus (VEEV), which causes flu-like symptoms leading to neurological symptoms in up to 14% of cases. Large outbreaks of VEEV can result in 10,000 s of human cases and mass equine death. We previously showed that mifepristone (RU486) has anti-VEEV activity (EC50 = 20 μM) and only limited cytotoxicity (CC50 > 100 μM), but a limitation in its use is its abortifacient activity resulting from its ability to antagonize the progesterone receptor (PR). Here we generate a suite of new mifepristone analogues with enhanced antiviral properties, succeeding in achieving >11-fold improvement in anti-VEEV activity with no detectable increase in toxicity. Importantly, we were able to derive a lead compound with an EC50 of 7.2 µM and no detectable PR antagonism activity. Finally, based on our SAR analysis we propose avenues for the further development of these analogues as safe and effective anti-VEEV agents.

Medical and surgical abortion for women living with HIV

BACKGROUND

The World Health Organization (WHO) guidelines for safe abortion recommend medical abortion with mifepristone and misoprostol or surgical abortion with vacuum aspiration or dilation and evacuation as safe and effective options for women. However, no specific clinical considerations are stipulated within these guidelines for women living with HIV. Concerns have been raised that women living with HIV may be at greater risk of adverse abortion outcomes compared to HIV-uninfected women due to immunosuppression, high rates of co-infection with other sexually transmitted infections, and possible contraindications between medications used for medical abortion and antiretroviral therapy regimens.

OBJECTIVES

Our primary objective was to assess the effectiveness and safety of medical versus surgical abortion among women living with HIV. Our secondary objectives were to: (1) compare outcomes of medical and surgical abortion between women living with HIV and women without HIV and (2) describe outcomes of medical and surgical abortion among women living with HIV.

SEARCH METHODS

We conducted our search on 17 April 2018. We searched for all published and unpublished trials and observational studies of medical and surgical abortion among women living with HIV. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO, CINAHL, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform using a combination of terms for abortion and HIV. We searched conference websites for relevant abstracts. We also sought unpublished data stratified by HIV status that could be newly analyzed.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs), non-RCTs, and observational studies. We considered: (1) studies on the effectiveness and safety of medical versus surgical abortion among women living with HIV; (2) studies comparing outcomes of abortion for both methods between women living with HIV and women without HIV; and (3) studies that described outcomes of abortion among women living with HIV.

DATA COLLECTION AND ANALYSIS

One review author screened the titles, abstracts, citation information, and descriptor terms for citations initially identified by the search. We obtained the full-text articles of all potentially eligible studies when these were available. Two review authors independently examined the full-text articles for compliance with the inclusion criteria and determination of final study selection. We planned to conduct meta-analysis if a sufficient number of studies (at least three) addressed the same research question and presented data on sufficiently comparable outcomes.

MAIN RESULTS

Of 3840 records screened, we identified just one conference abstract that met our inclusion criteria. This prospective cohort study assessed the efficacy and acceptability of home administration of misoprostol for early medical abortion among women living with HIV who were of less than 63 days amenorrhea in Ukraine. Medical abortion was effective in 65 of 68 cases (96%) examined. The small number of failures included incomplete abortion (n = 1), heavy bleeding (n = 1), and ongoing pregnancy (n = 1). There were no serious infections.

AUTHORS' CONCLUSIONS

Due to the paucity of studies, we were unable to determine if outcome differences exist between women living with HIV and women without HIV who undergo medical or surgical abortion. We found no evidence suggesting that medical or surgical abortions are unsafe for women living with HIV. While additional research would strengthen the evidence base, healthcare providers should not be deterred from providing access to safe abortion to their patients living with HIV.

An unhealthy relationship: viral manipulation of the nuclear receptor superfamily

The nuclear receptor (NR) superfamily is a diverse group of over 50 proteins whose function is to regulate the transcription of a vast array of cellular genes. These proteins are able to tune transcription over an extremely dynamic range due to the fact that they may act as either transcriptional activators or repressors depending on promoter context and ligand status. Due to these unique properties, diverse families of viruses have evolved strategies to exploit NRs in order to regulate expression of their own genes and to optimize the cellular milieu to facilitate the viral lifecycle. While the specific NRs targeted by these viruses vary, the strategies used to target them are common. This is accomplished at the cis-level by incorporation of nuclear receptor response elements into the viral genome and at the trans-level by viral proteins that target NRs directly or indirectly to modulate their function. The specific NR(s) targeted by a particular virus are likely to be reflective of the tissue tropism of the virus in question. Thus, the essential role played by NRs in the replication cycles of such diverse viruses underscores the importance of understanding their functions in the context of specific infections. This knowledge will allow appropriate considerations to be made when treating infected individuals with hormone-associated diseases and will potentially assist in the rational design of novel antiviral therapeutics.