Human T-Lymphotropic virus type 1 (HTLV-1) lifelong infects at least 5-10 million people worldwide, a minority of whom develop severe lethal diseases including adult T-cell Leukemia/lymphoma and HTLV-1-associated myelopathy or tropical spastic paraparesis. Currently, no vaccines or curative therapies to fight HTLV-1 infection or diseases are available. Recently we found that a tributyltin molecule, Bu3SnOCOCF3 (TBT), which is more potent than cisplatin in inducing cytotoxic effects towards a panel of cell lines including high-tumorigenic cells, also exerted potent cytotoxic effects even towards HTLV-1-infected cell lines, mimicking different states of virus-driven transformation. The type of cell death involved was elusive. In the present study, the effects of TBT on virological and cell death parameters were investigated in HTLV-1-infected immortalized lymphocytes generated by in vitro infection and rendered with or without progressive independence from interleukin-2 as a growth factor. Molecular studies demonstrated that TBT affected HTLV-1 viral gene expression, especially HBZ. TBT confirmed its high cytotoxic potential on the HTLV-1-infected cell lines assayed, especially towards the IL-2-independent HTLV-1-infected cells. Investigation of mechanisms involved in cell death induced by TBT in HTLV-1-infected cells confirmed that caspase 3 and 8 activation, as well as apoptotic response, were relevant. In addition, pyroptosis as well as other unspecifed forms of lytic death presumably contribute to cell death induced by TBT in HTLV-1-infected cells, while a concomitant activation of an autophagic response by this compound seems to mitigate it. Overall, these experimental results outline a particular profile of TBT-induced cell death in HTLV-1-infected cells that is useful for future studies aimed at verifying the real potential of tin-based compounds to contrast diseases caused by HTLV-1.

3D cell systems for in vitro experimental studies are able to mimic the in vivo efficacy of drugs before they are tested on animals. However, many studies are still needed in order to mimic the physiological environment with 3D cell-growth systems. The mechano-physical properties of the microenvironment are relevant for the invasiveness of cancer cells and for their drug resistance. In this study, 3D tumoroids of human oral squamous cell carcinoma (OSCC) CAL27 cells of different stiffnesses were produced using a tunable PEG-silk fibroin hydrogel (PSF), and the antitumor activity of the peptide CIGB300, an anticancer therapeutic peptide, with respect to these 3D tumoroid models was assessed. Furthermore, spectroscopic studies on the CIGB300 peptide are reported regarding its structure, stability, aggregation and diffusion properties. For the first time, the diffusion of the peptide CIGB300 in tunable silk fibroin hydrogels of different stiffnesses is investigated over time via fluorescence spectroscopy as a potential tool in drug-screening using hydrogel-based 3D tumoroids.

Among the metal-derived complexes, recently, tin derivatives have been investigated as promising anti-cancer drug candidates. Our previous study showed that the tin-based compound Bu3SnOCOCF3 (TBT) exerts cytotoxic activity on solid tumor cell lines. In the present study, the effects of TBT were evaluated in vitro on HTLV-1-infected human lymphocytic cell lines at different stages of viral transformation, consisting of IL-2-dependent (PB2/IL-2) and IL-2-independent (PB2/NO-IL-2) cells, generated in our laboratory by HTLV-1 in vitro infection of lymphocytes from the same donor, and the C91/PL cell line established by co-cultivation with T cells from a patient with HTLV-1-positive leukemia. TBT induced a reliable and reproducible dose-dependent inhibition of metabolic activity and viability in the HTLV-1-infected cells. The effect was cell-type-dependent, with C91/PL cells being quite resistant. An investigation into the cytotoxic effects induced by TBT in HTLV-1-infected cells and data on caspase inhibitors/caspase activation indicated that apoptotic cell death was involved, but also that the possible involvement of other forms of cell death could not be excluded. Taken together, the results show for the first time that the tin-based compound, although not devoid of a certain cytotoxicity toward uninfected cells, can induce typical and potent effects on HTLV-1-infected cells.

Additive carbonylations typically necessitate strong nucleophiles, such as alcohols or amines. In this study, we carbonylated a poorly nucleophilic urea, under oxidant-free conditions. Our straightforward carbonylative strategy enables access to versatile alpha,beta-unsaturated gamma-lactams featuring an aminocarbonyl fragment, utilizing readily available propargylic ureas as starting materials. The employment of the PdI2/KI catalytic system allowed complete regioselectivity (5-endo-dig), high functional group tolerance, broad substrate scope as well as operational simplicity (oxidant-free, organic ligand-free and base-free protocol). The synthetic utility of these gamma-lactams is showcased through late-stage functionalizations, such as Giese reactions and peptide couplings.

The human T-cell leukemia virus type 1 (HTLV-1) was first described in 1980. It is spread in highly endemic regions in the world, such as the Southwestern part of Japan, sub-Saharan Africa and South America, Caribbean, Middle East, and Australo-Melanesia regions. HTLV-1 causes adult T cell leukemia and is associated with many inflammatory conditions, most notably HTLV-1-associated myelopathy/tropic spastic paraparesis. HTLV-2, first isolated in 1982, was recognized as a common infection in intravenous drug users, but a clear association with disease remains elusive. The first estimate of HTLV-1-positive individuals worldwide, in 1993, was around 10-20 millions. Due to the lack of global population-based prevalence studies, this is considered an underestimate at the moment. Furthermore, HTLV-1 prevalence in Europe is impacted by changing migration flows. Particularly, no data on HTLV-1 prevalence in the general population in Italy are available. Here, we report a systematic literature review of studies conducted in Italy on HTLV-1/2 from 1980 to 2023. Based on the criteria we adopted a total of 426 publications were found (64 reviews, 99 epidemiological, and 263 translational studies). The contents of some representative publications are summarized and discussed. Moreover, an approximate estimation of about 26,000 HTLV-1 positive foreigners living in Italy was obtained from updated data of foreigners from each single country officially registered as resident in Italy and from data on HTLV-1 prevalence among the general population in the corresponding countries.

AbstractThe 30th workshop of the HTLV European Research Network (HERN) was held in Madrid on September 15–16, 2023. Over fifty researchers from Europe and America convened for a two-day conference to update and discuss basic science, epidemiology, clinical management and therapeutics for patients with HTLV-1 infection. Scientific topics addressed included new estimates for HTLV-1 in Europe; impact of antenatal screening on mother-to-child HTLV-1 infections; new insights into the molecular epidemiology of HTLV-1; reports of elite controllers for HTLV-1 infection; role of antiretrovirals as HTLV-1 pre-exposure prophylaxis; and prospects for a HTLV-1 vaccine. The group agreed to submit a formal request to WHO for increasing the global surveillance and awareness of HTLV-1. This viral infection is a potentially life-threatening, neglected condition with neither treatment nor vaccine. At this time, expanding HTLV-1 screening is the most effective way to reduce viral dissemination.

In the present work, we have designed and synthesized potential NSP5 protease allosteric inhibitors exploiting both docking and molecular dynamic data on SARS-CoV-2. The chemical protocols were developed on the basis of 1,3-dipolar cycloaddition reactions as well as the chemistry of nitrosocarbonyl intermediates. Computational studies were first conducted for determining the best candidate for SARS-CoV-2 NSP5 protease inhibition. Selected compounds were submitted to biological tests, showing low cytotoxicity and moderate activity.

Iminosugars' similarity to carbohydrates determines the exceptional potential for this class of polyhydroxylated alkaloids to serve as potential drug candidates for a wide variety of diseases such as diabetes, lysosomal storage diseases, cancer, bacterial and viral infections. The presence of lipophilic substituents has a significant impact on their biological activities. This work reports the synthesis of three new pyrrolidine lipophilic derivatives O-alkylated in C-6 position. The biological activities of our iminosugars' collection were tested in two cancer cell lines and, due to the pharmaceutical potential, in the model yeast system Saccharomyces cerevisiae to assess their toxicity.

Isoxazoline-carbocyclic monophosphate nucleotides were designed and synthesized through the chemistry of nitrosocarbonyl intermediates and stable anthracenenitrile oxide. Docking and molecular dynamics studies were first conducted for determining the best candidate for polymerase SARS-CoV-2 inhibition. The setup phosphorylation protocol afforded the nucleotides available for the biological tests. Preliminary inhibition and cytotoxicity assays were then performed, and the results showed a moderate activity of the nucleotides accompanied by cytotoxicity.

The human T-cell leukemia virus type 1 (HTLV-1) is the only known human oncogenic retrovirus. HTLV-1 can cause a type of cancer called adult T-cell leukemia/lymphoma (ATL). The virus is transmitted through the body fluids of infected individuals, primarily breast milk, blood, and semen. At least 5–10 million people in the world are infected with HTLV-1. In addition to ATL, HTLV-1 infection can also cause HTLV-I-associated myelopathy (HAM/TSP). ATL is characterized by a low viral expression and poor prognosis. The oncogenic mechanism triggered by HTLV-1 is extremely complex and the molecular pathways are not fully understood. However, viral regulatory proteins Tax and HTLV-1 bZIP factor (HBZ) have been shown to play key roles in the transformation of HTLV-1-infected T cells. Moreover, several studies have shown that the final fate of HTLV-1-infected transformed Tcell clones is the result of a complex interplay of HTLV-1 oncogenic protein expression with cellular transcription factors that subvert the cell cycle and disrupt regulated cell death, thereby exerting their transforming effects. This review provides updated information on the mechanisms underlying the transforming action of HTLV-1 and highlights potential therapeutic targets to combat ATL.

Metal-derived platinum complexes are widely used to treat solid tumors. However, systemic toxicity and tumor resistance to these drugs encourage further research into similarly effective compounds. Among others, organotin compounds have been shown to inhibit cell growth and induce cell death and autophagy. Nevertheless, the impact of the ligand structure and mechanisms involved in the toxicity of organotin compounds have not been clarified. In the present study, the biological activities of commercially available bis(tributyltin) oxide and tributyltin chloride, in comparison to those of specially synthesized tributyltin trifluoroacetate (TBT-OCOCF3) and of cisplatin, were assessed using cells with different levels of tumorigenicity. The results show that tributyltins were more cytotoxic than cisplatin in all the tested cell lines. NMR revealed that this was not related to the interaction with DNA but to the inhibition of glucose uptake into the cells. Moreover, highly tumorigenic cells were less susceptible than nontumorigenic cells to the nonunique pattern of death induced by TBT-OCOCF3. Nevertheless, tumorigenic cells became sensitive when cotreated with wortmannin and TBT-OCOCF3, although no concomitant induction of autophagy by the compound was detected. Thus, TBT-OCOCF3 might be the prototype of a family of potential anticancer agents.

Regulated cell death (RCD) plays an important role in the progression of viral replication and particle release in cells infected by herpes simplex virus-1 (HSV-1). However, the kind of RCD (apoptosis, necroptosis, others) and the resulting cytopathic effect of HSV-1 depends on the cell type and the species. In this study, we further investigated the molecular mechanisms of apoptosis induced by HSV-1. Although a role of caspase-8 has previously been suggested, we now clearly show that caspase-8 is required for HSV-1-induced apoptosis in a FADD-/death receptor-independent manner in both mouse embryo fibroblasts (MEF) and human monocytes (U937). While wild-type (wt) MEFs and U937 cells exhibited increased caspase-8 and caspase-3 activation and apoptosis after HSV-1 infection, respective caspase-8-deficient (caspase-8−/−) cells were largely impeded in any of these effects. Unexpectedly, caspase-8−/− MEF and U937 cells also showed less virus particle release associated with increased autophagy as evidenced by higher Beclin-1 and lower p62/SQSTM1 levels and increased LC3-I to LC3-II conversion. Confocal and electron microscopy revealed that HSV-1 stimulated a strong perinuclear multivesicular body response, resembling increased autophagy in caspase-8−/− cells, entrapping virions in cellular endosomes. Pharmacological inhibition of autophagy by wortmannin restored the ability of caspase-8−/− cells to release viral particles in similar amounts as in wt cells. Altogether our results support a non-canonical role of caspase-8 in both HSV-1-induced apoptosis and viral particle release through autophagic regulation.

Based on previous experience in our laboratory, we developed a real-time reverse transcriptase (RT) quantitative PCR (RT-qPCR) assay for the assessment of very low levels of HIV-1 RT activity. The RNA, acting as a template for reverse transcription into cDNA by HIV-1 RT, consisted of a synthetic RNA ad hoc generated by in vitro transcription and included a coding sequence for HSV-1 gD (gD-RNA-synt). Different conditions of variables involved in the RT-qPCR reaction, notably different amounts of gD-RNA-synt, different mixes of the reaction buffer, and different dNTP concentrations, were tested to optimize the assay. The results indicated that the gD-RNA-synt-based RT assay, in its optimized formulation, could detect a specific cDNA reverse transcription even in the presence of 1 × 10−9 U of HIV RT. This achievement greatly improved the sensitivity of the assay over previous versions. In summary, this constructed RT-qPCR assay may be considered a promising tool for providing accurate information on very low HIV-1 RT activity.

The Cover Feature shows the fluorescence microscopy image inserted in a Petri dish of representative slides showing the effects of active isoxazolidine N,O-nucleoside treatment on U937 cells. The N,O-nucleoside was prepared through N-glycosilation (Vorbrüggen protocol) with 6-chloropurine of the anti-Markovnikov ene adduct of the anthracene nitrosocarbonyl intermediate with trans-cinnamyl alcoho. More information can be found in the Full Paper by Andrea Marraffa et al.

The human T cell leukemic/lymphotropic virus type 1 (HTLV-1), discovered several years ago, is the causative agent for a rapid progressive haematological malignancy, adult T cell leukemia (ATL), for debilitating neurological diseases and for a number of inflammatory based diseases. Although the heterogeneous features of the diseases caused by HTLV-1, a common topic concerning related therapeutic treatments relies on the use of antiretrovirals. This review will compare the different approaches and opinions in this matter, giving a concise overview of preclinical as well as clinical studies covering all the aspects of antiretrovirals in HTLV-1 infection. Studies will be grouped on the basis of the class of antiretroviral, putting together both pre-clinical and clinical results and generally following a chronological order. Analysis of the existing literature highlights that a number of preclinical studies clearly demonstrate that different classes of antiretrovirals, already utilized as anti-HIV agents, are actually capable to efficiently contrast HTLV-1 infection. Nevertheless, the results of most of the clinical studies are generally discouraging on the same point. In conclusion, the design of new antiretrovirals more specifically focused on HTLV-1 targets, and/or the establishment of early treatments with antiretrovirals could hopefully change the perspectives of diseases caused by HTLV-1.

Testing HIV-1 RNA in plasma by PCR is universally accepted as the ultimate standard to confirm diagnosis of HIV-1 infection and to monitor viral load in patients under treatment. However, in some cases, this assay could either underestimate or overestimate the replication capacity of a circulating or latent virus. In the present study, we performed the assessment of evaluating the HIV-1 reverse transcriptase (RT) activity by means of a new assay for the functional screening of the status of HIV-1 patients. To this purpose, we utilized, for the first time on blood samples, an adapted version of a real-time RT quantitative PCR assay, utilized to evaluate the HIV-1-RT inhibitory activity of compounds. The study analyzed blood samples from 28 HIV-1-infected patients, exhibiting a wide range of viremia and immunological values. Results demonstrated that plasma HIV-1 RT levels, expressed as cycle threshold values obtained with the assay under appraisal, were inversely and highly significantly correlated with the plasma HIV-1-RNA levels of the patients. Thus, an HIV-1 RT quantitative PCR assay was created which we describe in this study, and it may be considered as a promising basis for an additional tool capable of furnishing information on the functional virological status of HIV-1-infected patients.

Adult T cell leukemia/lymphoma (ATL) can be susceptible, at least transiently, to treatments with azidothymidine (AZT) plus IFNα and/or arsenic trioxide. However, the real role of AZT in this effect is still unclear. In fact, while reverse transcriptase (RT) inhibition could explain reduction of clonal expansion and of renewal of HTLV-1 infected cells during ATL progression, this effect alone seems insufficient to justify the evident and prompt decrease of the pro-viral load in treated patients. We have previously demonstrated that AZT is endowed with an intrinsic pro-apoptotic potential towards both peripheral blood mononuclear cells from healthy donors or some tumor cell lines, but this cytotoxic potential cannot be fully achieved unless IκBα phosphorylation is inhibited. Since the constitutive activation of NF-kappa B (NF-κB) appears a common biological basis of HTLV-1-infected cells, a pharmacological inhibition of IκBα phosphorylation seems a potential strategy for treating and preventing HTLV-1 related pathologies. In this study, we have demonstrated that a combination treatment with the IκBα phosphorylation inhibitor Bay 11-7085 and AZT induced increased levels of regulated cell death (RCD) by apoptosis compared to the single treatments in HTLV-1 infected cells of different origin. Importantly, levels of RCD were considerably higher in infected cells in comparison with the uninfected ones. Inhibition of NF-κB activation following the combined treatment was confirmed by analysis of both gel-shift and functional activity of the NF-κB complex proteins, p65/p52. Moreover, a transcriptional analysis revealed that the addition of Bay 11-7085 to AZT treatment in HTLV-1-infected cells modified their transcriptional profile, by inducing the upregulation of some pro-apoptotic genes together with the downregulation of some anti-apoptotic genes. Our data suggest that addition of adequate concentrations of IκBα phosphorylation inhibitor to therapeutic regimens including AZT could be a promising strategy in ATL.

Abstract Two new families of N,O‐nucleoside analogues containing the anthracene moiety introduced through the nitrosocarbonyl ene reaction with allylic alcohols were prepared. The core structure is an isoxazolidine heterocycle that introduces either atom either a phenyl ring or dimethyl moiety at the C3 carbon. Different heterobases were inserted at the position 5 of the heterocyclic ring. One of the synthesized compounds demonstrated a good capacity to induce cell death and an appreciable nuclear fragmentation was evidenced in treated cells.

The pyrimidine nucleus is a versatile core in the development of antiretroviral agents. On this basis, a series of pyrimidine-2,4-diones linked to an isoxazolidine nucleus have been synthesized and tested as nucleoside analogs, endowed with potential anti-HIV (human immunodeficiency virus) activity. Compounds 6a–c, characterized by the presence of an ethereal group at C-3, show HIV reverse transcriptase (RT) inhibitor activity in the nanomolar range as well as HIV-infection inhibitor activity in the low micromolar with no toxicity. In the same context, compound 7b shows only a negligible inhibition of RT HIV.

Herpes simplex virus 1 (HSV-1) can infect a wide range of cell types, including cells of the adaptive and innate immunity but, normally, it completes a fully-permissive replication cycle only in epithelial or neural cells. Complex mechanisms controlling this delicate balance in immune cells and consequent restriction of HSV-1 infection in these cells have not been completely elucidated. We have recently demonstrated that the transcription factor nuclear factor kappa B (NF-κB) can act as a main permissiveness regulator of HSV-1 infection in monocytic cells, however, mediators involved in this regulation have not been identified. To better define mechanisms involved in this phenomenon and, particularly, the possible involvement of ROS, wild type U937 cells or U937 cells stably transfected with a dominant-negative (DN) IκB-mutant and selenium-containing compounds, as anti-oxidants, were utilized. The main results can be summarized as follows. HSV-1 infection induces an immediate ROS production in U937 monocytic cells that can efficiently activate NF-κB but not in DN-IκB-mutant cells. Treatment with selenium-containing antioxidants efficiently inhibited HSV-1-induced ROS generation while producing increased levels of HSV-1 replication and a reduction of HSV-1-induced NF-κB activation in U937 monocytic cells. Our results suggest a scenario in which an efficient NF-κB-dependent ROS production in response to infection could contribute in limiting HSV-1 replication in monocytes/macrophages, thus avoiding possible irreparable damage to the innate immune system of the host during HSV-1 infection.