The Use of Ribavirin as an Anticancer Therapeutic: Will It Go Viral?

RNA-binding proteins as therapeutic targets in cancer

RNA-binding proteins (RBPs) have emerged as critical regulators of cancer progression, influencing virtually all hallmarks of cancer. Their ability to modulate gene expression patterns that promote or inhibit tumorigenesis has positioned RBPs as promising targets for novel anti-cancer therapies. This mini-review summarizes the current state of RBP-targeted cancer treatments, focusing on five examples, eIF4F, FTO, SF3B1, RBM39 and nucleolin. We highlight the diversity of current targeting approaches and discuss ongoing challenges including the complexity of RBP regulatory networks, potential off-target effects and the need for more specific targeting methods. By assessing the future potential of novel therapeutic avenues, we provide insights into the evolving landscape of cancer treatment and the critical role RBPs may play in next-generation therapeutics.

Strengths and limitations of the worm development and activity test (wDAT) as a chemical screening tool for developmental hazards

The worm Development and Activity Test (wDAT) measures C. elegans developmental milestone acquisition timing and stage-specific spontaneous locomotor activity (SLA). Previously, the wDAT identified developmental delays and SLA level changes in C. elegans with mammalian developmental toxicants arsenic, lead, and mercury. 5-fluorouracil (5FU), cyclophosphamide (CP), hydroxyurea (HU), and ribavirin (RV) are teratogens that also induce growth retardation in developing mammals. In at least some studies on each of these chemicals, fetal weight reductions were seen at mammalian exposures below those that had teratogenic effects, suggesting that screening for developmental delay in a small alternative whole-animal model could act as a general toxicity endpoint to identify chemicals for further testing for more specific adverse developmental outcomes. Consistent with mammalian developmental effects, 5FU, HU, and RV were associated with developmental delays with the wDAT. Exposures associated with developmental delay induced hypoactivity with 5FU and HU, but slight hyperactivity with RV. CP is a prodrug that requires bioactivation by cytochrome P450s for both therapeutic and toxic effects. CP tests as a false negative in several in vitro assays, and it was also a false negative with the wDAT. These results suggest that the wDAT has the potential to identify some developmental toxicants, and that a positive wDAT result with an unknown may warrant further testing in mammals. Further assessment with larger panels of positive and negative controls will help qualify the applicability and utility of this C. elegans wDAT assay within toxicity test batteries or weight of evidence approaches for developmental toxicity assessment.

Computational and biological approaches in repurposing ribavirin for lung cancer treatment: Unveiling antitumorigenic strategies

Lung cancer is among leading causes of death worldwide. The five-year survival rate of this disease is extremely low (17.8 %), mainly due to difficult early diagnosis and to the limited efficacy of currently available chemotherapeutics. This underlines the necessity to develop innovative therapies for lung cancer. In this context, drug repurposing represents a viable approach, as it reduces the turnaround time of drug development removing costs associated to safety testing of new molecular entities. Ribavirin, an antiviral molecule used to treat hepatitis C virus infections, is particularly promising as repurposed drug for cancer treatment, having shown therapeutic activity against glioblastoma, acute myeloid leukemia, and nasopharyngeal carcinoma. In the present study, we thoroughly investigated the in vitro anticancer activity of ribavirin against A549 human lung adenocarcinoma cells. From a functional standpoint, ribavirin significantly inhibits cancer hallmarks such as cell proliferation, migration, and colony formation. Mechanistically, ribavirin downregulates the expression of numerous proteins and genes regulating cell migration, proliferation, apoptosis, and cancer angiogenesis. The anticancer potential of ribavirin was further investigated in silico through gene ontology pathway enrichment and protein-protein interaction networks, identifying five putative molecular interactors of ribavirin (Erb-B2 Receptor Tyrosine Kinase 4 (Erb-B4); KRAS; Intercellular Adhesion Molecule 1 (ICAM-1); amphiregulin (AREG); and neuregulin-1 (NRG1)). These interactions were characterized via molecular docking and molecular dynamic simulations. The results of this study highlight the potential of ribavirin as a repurposed chemotherapy against lung cancer, warranting further studies to ascertain the in vivo anticancer activity of this molecule.

Development of an Intranasal In Situ System for Ribavirin Delivery: In Vitro and In Vivo Evaluation

Recently, ribavirin has demonstrated effectiveness in treating glioblastoma through intranasal administration utilizing the nose-to-brain delivery route. Enhancing ribavirin's bioavailability can be achieved by utilizing intranasal stimuli-responsive systems that create a gel on the nasal mucosa. The research examined thermosensitive, pH-sensitive, and ion-selective polymers in various combinations and concentrations, chosen in line with the current Quality by Design (QbD) approach in pharmaceutical development. Following a thorough assessment of key parameters, the optimal composition of gellan gum at 0.5%, Poloxamer 124 at 2%, and purified water with ribavirin concentration at 100 mg/mL was formulated and subjected to in vivo testing. Through experiments on male rats, the nose-to-brain penetration mechanism of the active pharmaceutical ingredient (API) was elucidated, showcasing drug accumulation in the olfactory bulbs and brain.

Vaccine approaches and treatment aspects against Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever [CCHF] is a severe infectious viral disease caused by a tick borne virus which can lead to fatal hemorrhagic disease in humans. It has been reported from some continents including Africa, Asia and Europe. Virus is transmitted to human mainly through tick bite, whose acquire infection from reservoirs wild and domesticated mammalians and ostriches. Currently no approved vaccine or drug is available for CCHF and prevention is mainly based on biosecurity measures. Ribavirin is the only approved drug that has been used in some countries to treat human disease, however some new studies did not prove the Ribavirin efficacy. Different strategies to design effective vaccines, have been conducted through years, from inactivated virus to nucleotide-based ones including DNA and mRNA vaccines. In this study we review of pioneering vaccine candidate platforms.

Comparison of anti-cancer effects of platinum ribavirin and ribavirin via telomerase and Bcl-2 gene expression

Among the common treatments for cancers, chemotherapy is widely used. One of the ways to evaluate the effectiveness of anti-cancer drugs is by checking the expression of tumor markers. Hence, this study aimed to evaluate the anti-cancer effects of the newly synthesized platinum ribavirin (Pt-Rb) compared to ribavirin (Rb) through biomarkers. In this study, cell lines were divided into four groups: groups A and B as healthy negative control group and untreated cancer group respectively. Group C and D were treated with, Rb and Pt-Rb, a novel anti-cancer drug, respectively. After evaluating LC50 for the drugs by MTT test, the expression of telomerase and Bcl-2 (B cell lymphoma-2) genes was evaluated using real-time PCR (RT-qPCR). The results showed a significant decrease in telomerase (0.020 ± 0.007) and Bcl-2(0.120 ± 0.005) gene expression in cancer cells treated with Pt-Rb (group D) compared to telomerase (0.040 ± 0.014) and Bcl-2(0.220 ± 0.014) treated with Rb (group C) and also between group D and telomerase (70.76 ± 0.330) and Bcl-2 (99.52 ± 0.670) in group B. The majority of the groups under investigation showed a significant difference (p < 0.05), suggesting that Pt-Rb had stronger anti-cancer effects than Rb and untreated cancer cells. Additionally, Pt-Rb treatment results demonstrated more increased apoptosis than Rb. Our results demonstrated that Pt-Rb is an effective medication in cancer treatment by lowering anti-apoptotic indicators. Therefore, this chemical has the potential to be an effective anti-cancer therapy, pending further research on animal models and then human volunteers.

Effect of anti-COVID-19 drugs on patients with cancer

The clinical treatment of patients with cancer who are also diagnosed with coronavirus disease (COVID-19) has been a challenging issue since the outbreak of COVID-19. Therefore, it is crucial to understand the effects of commonly used drugs for treating COVID-19 in patients with cancer. Hence, this review aims to provide a reference for the clinical treatment of patients with cancer to minimize the losses caused by the COVID-19 pandemic. In this study, we also focused on the relationship between COVID-19, commonly used drugs for treating COVID-19, and cancer. We specifically investigated the effect of these drugs on tumor cell proliferation, migration, invasion, and apoptosis. The potential mechanisms of action of these drugs were discussed and evaluated. We found that most of these drugs showed inhibitory effects on tumors, and only in a few cases had cancer-promoting effects. Furthermore, inappropriate usage of these drugs may lead to irreversible kidney and heart damage. Finally, we have clarified the use of different drugs, which can provide useful guidance for the clinical treatment of cancer patients diagnosed with COVID-19.

Developments in the chemistry and biology of 1,2,3-triazolyl-C-nucleosides

In the last 50 years, nucleoside analogs have been introduced to drug therapy as antivirals for different types of cancer due to their interference in cellular proliferation. Among the first line of nucleoside treatment drugs, ribavirin (RBV) is a synthetic N-nucleoside with a 1,2,4-triazole moiety that acts as a broad-spectrum antiviral. It is on the World Health Organization (WHO) list of essential medicines. However, this important drug therapy causes several side effects due to its nonspecific mechanism of action. There is thus a need for a continuous study of its scaffold. A particular approach consists of connecting  d-ribose to the nitrogen-containing base with a C-C bond. It provides more stability against enzymatic action and a better pharmacologic profile. The coronavirus disease (COVID) pandemic has increased the need for more solutions for the treatment of viral infections. Among these solutions, remdesivir, the first C-nucleoside, has been approved by the Food and Drug Administration (FDA) for clinical use against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It drew attention to the study of the C-nucleoside scaffold. Different C-nucleoside patterns have been synthesized over the years. They show many important activities against viruses and cancer cell lines. 1,2,3-Triazolyl-C-nucleoside derivatives are a prolific and efficient subclass of RBV analogs close to the already-known RBV with a C-C bond modification. These compounds are often prepared by alkynylation of the  d-ribose ring followed by azide-alkyne cycloaddition. They are reported to be active against the Crimean-Congo hemorrhagic fever virus and several tumoral cell lines, showing promising biological potential. In this review, we explore such approaches to 1,2,3-triazolyl-C-nucleosides and their evolution over the years.

Ribavirin attenuates carcinogenesis by downregulating IL-6 and IL-8 in vitro in human lung adenocarcinoma

Lung cancer is one of the leading causes of death worldwide, whereby the major contributing factors are cigarette smoking and exposure to environmental pollutants. Despite the availability of numerous treatment options, including chemotherapy, the five-year survival rate is still extremely low, highlighting the urgent need to develop novel, more effective therapeutic strategies. In this context, the repurposing of previously approved drugs is an advantage in terms of time and resources invested. Ribavirin is an antiviral drug approved for the treatment of hepatitis C, which shows potential for repurposing as an anticancer agent. Among the many signaling molecules promoting carcinogenesis, the interleukins (ILs) IL-6 and IL-8 are interesting therapeutic targets as they promote a variety of cancer hallmarks such as cell proliferation, migration, metastasis, and angiogenesis. In the present study, we show that ribavirin significantly downregulates the expression of IL-6 and IL-8 in vitro in A549 human lung adenocarcinoma cells. The results of this study shed light on the anticancer mechanisms of ribavirin, providing further proof of its potential as a repurposed drug for the treatment of lung cancer.

Identification of γ-Fagarine as a novel antiviral agent against respiratory virus (hMPV) infection

Human metapneumovirus (hMPV) causes significant upper and lower respiratory disease in all age groups worldwide. However, there is no licensed drugs or vaccine available against hMPV. γ-Fagarine, an alkaloid isolated from the root of zanthoxylum, has been reported to be effective in the treatment of cancer, inflammatory diseases and antivirals. However, little is known about the inhibitory effect of γ-Fagarine against respiratory virus infection and the mechanism. In this study, we aim to investigate the effect of γ-Fagarine on hMPV infection and explore its underlying molecular mechanisms. Vero-E6 and 16HBE cells were used as cell models. Virus replication and microcosm character were explored in Vero-E6 cells. Then, the antiviral activities were investigated by quantitative real-time PCR (RT-qPCR), western blotting (WB), and indirect immunofluorescence assays (IFAs) in Vero-E6 and 16HBE. Potential mechanisms of γ-Fagarine related to HSPG and lysosome pH were assessed in 16HBE cells. Lastly, a virus-infected mouse model was established and antiviral assay in vivo was conducted. γ-Fagarine showed no toxicity toward Vero-E6 cells and 16HBE cells but demonstrated anti-hMPV activity. Virus titers of γ-Fagarine group were reduced to 33% and 45% of the hMPV groups, respectively. Besides, mechanistic studies revealed that γ-Fagarine could inhibit hMPV by dual mechanisms of direct restraining virus binding with HSPG and influencing lysosome pH. Furthermore, oral delivery of γ-Fagarine to hMPV-infected mice at a dosage of 25 mg/kg reduced the hMPV load in lung tissues. After γ-Fagarine treatment, pathological damage caused by viral infection was also ameliorated. These findings suggest that γ-Fagarine has antiviral effects in vitro and in vivo, which are associated with its ability to restrain virus binding with HSPG and influence lysosome pH, thus indicating that γ-Fagarine has the potential to serve as a candidate to fight against hMPV infection and other respiratory viruses such as influenza viruses and SARS-CoV-2.

The Neurodevelopmental and Molecular Landscape of Medulloblastoma Subgroups: Current Targets and the Potential for Combined Therapies

Medulloblastoma is the most common malignant pediatric brain tumor and is associated with significant morbidity and mortality in the pediatric population. Despite the use of multiple therapeutic approaches consisting of surgical resection, craniospinal irradiation, and multiagent chemotherapy, the prognosis of many patients with medulloblastoma remains dismal. Additionally, the high doses of radiation and the chemotherapeutic agents used are associated with significant short- and long-term complications and adverse effects, most notably neurocognitive delay. Hence, there is an urgent need for the development and clinical integration of targeted treatment regimens with greater efficacy and superior safety profiles. Since the adoption of the molecular-based classification of medulloblastoma into wingless (WNT) activated, sonic hedgehog (SHH) activated, group 3, and group 4, research efforts have been directed towards unraveling the genetic, epigenetic, transcriptomic, and proteomic profiles of each subtype. This review aims to delineate the progress that has been made in characterizing the neurodevelopmental and molecular features of each medulloblastoma subtype. It further delves into the implications that these characteristics have on the development of subgroup-specific targeted therapeutic agents. Furthermore, it highlights potential future avenues for combining multiple agents or strategies in order to obtain augmented effects and evade the development of treatment resistance in tumors.

Metabolomics study of ribavirin in the treatment of orthotopic lung cancer based on UPLC-Q-TOF/MS

Ribavirin is a common antiviral drug, especially for patients with hepatitis C. Our recent studies demonstrated that ribavirin showed anti-tumor activity in colorectal cancer and hepatocellular carcinoma, but its effects on lung cancer remains unclear. This study aimed to evaluate the anti-tumor activity of ribavirin against lung cancer and elucidate the underlying mechanism. We established orthotopic mouse model of lung cancer (LLC and GLC-82) and employed an ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based metabolomics approach. We found that ribavirin significantly inhibited the proliferation and colony formation of lung cancer cells. Tumor sizes of orthotopic lung cancer in ribavirin-treated groups were also significantly lower than those in control groups. Metabolomics analysis revealed that ribavirin mainly affected 5 metabolic pathways in orthotopic lung tumor models, taurine and hypotaurine metabolism, nicotinate and nicotinamide metabolism, linoleic acid metabolism, arginine biosynthesis and arachidonic acid metabolism. Furthermore, we identified 5 upregulated metabolites including β-nicotinamide adenine dinucleotide (NAD⁺), nicotinamide (NAM), taurine, ornithine and citrulline, and 7 downregulated metabolites including 1-methylnicotinamide (MNAM), S-adenosyl-l-homocysteine (SAH), N1-Methyl-2-pyridone-5-carboxamide (2PY), homocysteine (Hcy), linoleic acid, arachidonic acid (AA) and argininosuccinic acid in ribavirin-treated groups. These results provide new insight into the anti-tumor mechanism of ribavirin for lung cancer.

On the human health benefits of microalgal phytohormones: An explorative in silico analysis

Phytohormones represent a group of secondary metabolites with different chemical structures, in which belong auxins, cytokinins, gibberellins, or brassinosteroids. In higher plants, they cover active roles in growth or defense function, while their potential benefits for human health protection were noted for some phytohormones and little explored for many others. In this study, we developed a target fishing strategy on fifty-three selected naturally occurring phytohormones covering different families towards proteins involved in key cellular functions related to human metabolism and health protection/disease. This in silico analysis strategy aims to screen the potential human health-driven bioactivity of more than fifty phytohormones through the analysis of their interactions with specific targets. From this analysis, twenty-eight human targets were recovered. Some targets e.g., the proteins mitochondrial glutamate dehydrogenase (GLUD1) or nerve growth factor (NGF) bound many phytohormones, highlighting their involvement in amino acid metabolism and/or in the maintenance or survival of neurons. Conversely, some phytohormones specifically interacted with some proteins, e.g., SPRY domain-containing SOCS box protein 2 (SPSB2) or Inosine-5'-monophosphate dehydrogenase 1 (IMPDH1), both involved in human immune response. They were then investigated with a molecular docking analysis approach. Our bioprospecting study indicated that many phytohormones may endow human health benefits, with potential functional role in multiple cellular processes including immune response and cell cycle progression.

Compartmentalization and regulation of GTP in control of cellular phenotypes

Genetic or pharmacological inhibition of enzymes involved in GTP biosynthesis has substantial biological effects, underlining the need to better understand the function of GTP levels in regulation of cellular processes and the significance of targeting GTP biosynthesis enzymes for therapeutic intervention. Our current understanding of spatiotemporal regulation of GTP metabolism and its role in physiological and pathological cellular processes is far from complete. Novel methodologies such as genetically encoded sensors of free GTP offered insights into intracellular distribution and function of GTP molecules. In the current Review, we provide analysis of recent discoveries in the field of GTP metabolism and evaluate the key enzymes as molecular targets.

The hedgehog pathway in hematopoiesis and hematological malignancy

The Hedgehog (HH) pathway is a promising therapeutic target in hematological malignancies. Activation of the pathway has been tied to greater chances of relapse and poorer outcomes in several hematological malignancies and inhibiting the pathway has improved outcomes in several clinical trials. One inhibitor targeting the pathway via the protein Smoothened (SMO), glasdegib, has been approved by the FDA for use with a low dose cytarabine regiment in some high-risk acute myeloid leukemia patients (AML). If further clinical trials in glasdegib produce positive results, there may soon be more general use of HH inhibitors in the treatment of hematological malignancies.While there is clinical evidence that HH inhibitors may improve outcomes and help prevent relapse, a full understanding of any mechanism of action remains elusive. The bulk of AML cells exhibit primary resistance to SMO inhibition (SMOi), leading some to hypothesize that that clinical activity of SMOi is mediated through modulation of self-renewal and chemoresistance in rare cancer stem cells (CSC). Direct evidence that CSC are being targeted in patients by SMOi has proven difficult to produce, and here we present data to support the alternative hypothesis that suggests the clinical benefit observed with SMOi is being mediated through stromal cells in the tumor microenvironment.This paper's aims are to review the history of the HH pathway in hematopoiesis and hematological malignancy, to highlight the pre-clinical and clinical evidence for its use a therapeutic target, and to explore the evidence for stromal activation of the pathway acting to protect CSCs and enable self-renewal of AML and other diseases. Finally, we highlight gaps in the current data and present hypotheses for new research directions.

Anti-HCV and Zika activities of ribavirin C-nucleosides analogues

Ribavirin is an unnatural nucleoside exhibiting broad spectrum of antiviral and antitumor activities, still very widely studied particularly in a repositioning approach. C-triazolyl nucleoside analogues of ribavirin have been synthesized, as well as prodrugs and glycosylated or peptide conjugates to allow a better activity by vectorization into the liver or by facilitating uptake into the cells. The antiviral properties of all synthesized compounds have been evaluated in vitro against two important human viral pathogens belonging to the Flaviviridae family: hepatitis C virus (HCV) and Zika virus (ZIKV). There are no therapeutic options for Zika virus, whereas those available for HCV can be still improved. Our results indicated that compound 2 carrying an N-hydroxy carboxamide function exhibits the most inhibitory activities against both viruses. This compound moderately inhibited the propagation of HCV with an IC₅₀ value of 49.1 μM and Zika virus with an IC₅₀ of 33.2 μM comparable to ribavirin in the Vero cell line. The results suggest that compound 2 and its new derivatives may be candidates for further development of new anti-HCV and anti-ZIKV antiviral drugs.

Synthesis of ribavirin 1,2,3- and 1,2,4-triazolyl analogs with changes at the amide and cytotoxicity in breast cancer cell lines

We report the synthesis and cytotoxicity in MCF-7 and MDA-MB-231 breast cancer cells of novel 1,2,3- and 1,2,4-triazolyl analogs of ribavirin. We modified ribavirin's carboxamide moiety to test the effects of lipophilic groups. 1-β-D-Ribofuranosyl-1H-1,2,3-triazoles were prepared using Click Chemistry, whereas an unprecedented application of a prior 1,2,4-triazole ring synthesis was used for 1-β-D-ribofuranosyl-1H-1,2,4-triazole analogs. Though cytotoxicity was mediocre and there was no correlation with lipophilicity, we discovered that a structurally similar concentrative nucleoside transporter 2 (CNT2) inhibitor was modestly cytotoxic (MCF-7 IC₅₀ of 42 µM). These syntheses could be used to efficiently investigate variation in the nucleobase.

A Review: PI3K/AKT/mTOR Signaling Pathway and Its Regulated Eukaryotic Translation Initiation Factors May Be a Potential Therapeutic Target in Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a malignant tumor developing from the esophageal squamous epithelium, and is the most common histological subtype of esophageal cancer (EC). EC ranks 10th in morbidity and sixth in mortality worldwide. The morbidity and mortality rates in China are both higher than the world average. Current treatments of ESCC are surgical treatment, radiotherapy, and chemotherapy. Neoadjuvant chemoradiotherapy plus surgical resection is recommended for advanced patients. However, it does not work in the significant promotion of overall survival (OS) after such therapy. Research on targeted therapy in ESCC mainly focus on EGFR and PD-1, but neither of the targeted drugs can significantly improve the 3-year and 5-year survival rates of disease. Phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is an important survival pathway in tumor cells, associated with its aggressive growth and malignant progression. Specifically, proliferation, apoptosis, autophagy, and so on. Related genetic alterations of this pathway have been investigated in ESCC, such as PI3K, AKT and mTOR-rpS6K. Therefore, the PI3K/AKT/mTOR pathway seems to have the capability to serve as research hotspot in the future. Currently, various inhibitors are being tested in cells, animals, and clinical trials, which targeting at different parts of this pathway. In this work, we reviewed the research progress on the PI3K/AKT/mTOR pathway how to influence biological behaviors in ESCC, and discussed the interaction between signals downstream of this pathway, especially eukaryotic translation initiation factors (eIFs) and the development and progression of ESCC, to provide reference for the identification of new therapeutic targets in ESCC.

Computationally repurposing drugs for breast cancer subtypes using a network-based approach

‘De novo’ drug discovery is costly, slow, and with high risk. Repurposing known drugs for treatment of other diseases offers a fast, low-cost/risk and highly-efficient method toward development of efficacious treatments. The emergence of large-scale heterogeneous biomolecular networks, molecular, chemical and bioactivity data, and genomic and phenotypic data of pharmacological compounds is enabling the development of new area of drug repurposing called ‘in silico’ drug repurposing, i.e., computational drug repurposing (CDR). The aim of CDR is to discover new indications for an existing drug (drug-centric) or to identify effective drugs for a disease (disease-centric). Both drug-centric and disease-centric approaches have the common challenge of either assessing the similarity or connections between drugs and diseases. However, traditional CDR is fraught with many challenges due to the underlying complex pharmacology and biology of diseases, genes, and drugs, as well as the complexity of their associations. As such, capturing highly non-linear associations among drugs, genes, diseases by most existing CDR methods has been challenging. We propose a network-based integration approach that can best capture knowledge (and complex relationships) contained within and between drugs, genes and disease data. A network-based machine learning approach is applied thereafter by using the extracted knowledge and relationships in order to identify single and pair of approved or experimental drugs with potential therapeutic effects on different breast cancer subtypes. Indeed, further clinical analysis is needed to confirm the therapeutic effects of identified drugs on each breast cancer subtype.

Synthesis of novel C-nucleoside analogues bearing an anomeric cyano and a 1,2,3-triazole nucleobase as potential antiviral agents

A linear sequence to access a novel series of C-nucleosides bearing a quaternary carbon at the anomeric position tethered to a 4-substituted 1,2,3-triazole ring is described. Most of the compounds were obtained from a C-1 alkynyl furanoside, by a tandem or two-step CuAAC/functionalisation sequence, along with a diastereoselective cyanation of the furanoside derivatives in acidic conditions.

RNA-binding proteins and cancer metastasis

RNA-binding proteins (RBPs) can regulate gene expression through post-transcriptionally influencing all manner of RNA biology, including alternative splicing (AS), polyadenylation, stability, and translation of mRNAs, as well as microRNAs (miRNAs) and circular RNAs (circRNAs) processing. There is accumulating evidence reinforcing the perception that dysregulation or dysfunction of RBPs can lead to various human diseases, including cancers. RBPs influence diverse cancer-associated cellular phenotypes, such as proliferation, apoptosis, senescence, migration, invasion, and angiogenesis, contributing to the initiation and development of tumors, as well as clinical prognosis. Metastasis is the leading cause of cancer-related recurrence and death. Therefore, it is necessary to elucidate the molecular mechanisms behind tumor metastasis. In fact, a growing body of published research has proved that RBPs play pivotal roles in cancer metastasis. In this review, we will summarize the recent advances for helping us understand the role of RBPs in tumor metastasis, and discuss dysfunctions and dysregulations of RBPs affecting metastasis-associated processes including epithelial-mesenchymal transition (EMT), migration, and invasion of cancer cells. Furthermore, we will discuss emerging RBP-based strategy for the treatment of cancer metastasis.

Inosine and its methyl derivatives: Occurrence, biogenesis, and function in RNA

Inosine is one of the most common post-transcriptional modifications. Since its discovery, it has been noted for its ability to contribute to non-Watson-Crick interactions within RNA. Rapidly accumulating evidence points to the widespread generation of inosine through hydrolytic deamination of adenosine to inosine by different classes of adenosine deaminases. Three naturally occurring methyl derivatives of inosine, i.e., 1-methylinosine, 2'-O-methylinosine and 1,2'-O-dimethylinosine are currently reported in RNA modification databases. These modifications are expected to lead to changes in the structure, folding, dynamics, stability and functions of RNA. The importance of the modifications is indicated by the strong conservation of the modifying enzymes across organisms. The structure, binding and catalytic mechanism of the adenosine deaminases have been well-studied, but the underlying mechanism of the catalytic reaction is not very clear yet. Here we extensively review the existing data on the occurrence, biogenesis and functions of inosine and its methyl derivatives in RNA. We also included the structural and thermodynamic aspects of these modifications in our review to provide a detailed and integrated discussion on the consequences of A-to-I editing in RNA and the contribution of different structural and thermodynamic studies in understanding its role in RNA. We also highlight the importance of further studies for a better understanding of the mechanisms of the different classes of deamination reactions. Further investigation of the structural and thermodynamic consequences and functions of these modifications in RNA should provide more useful information about their role in different diseases.

Drug Repurposing for Glioblastoma and Current Advances in Drug Delivery-A Comprehensive Review of the Literature

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults with an extremely poor prognosis. There is a dire need to develop effective therapeutics to overcome the intrinsic and acquired resistance of GBM to current therapies. The process of developing novel anti-neoplastic drugs from bench to bedside can incur significant time and cost implications. Drug repurposing may help overcome that obstacle. A wide range of drugs that are already approved for clinical use for the treatment of other diseases have been found to target GBM-associated signaling pathways and are being repurposed for the treatment of GBM. While many of these drugs are undergoing pre-clinical testing, others are in the clinical trial phase. Since GBM stem cells (GSCs) have been found to be a main source of tumor recurrence after surgery, recent studies have also investigated whether repurposed drugs that target these pathways can be used to counteract tumor recurrence. While several repurposed drugs have shown significant efficacy against GBM cell lines, the blood–brain barrier (BBB) can limit the ability of many of these drugs to reach intratumoral therapeutic concentrations. Localized intracranial delivery may help to achieve therapeutic drug concentration at the site of tumor resection while simultaneously minimizing toxicity and side effects. These strategies can be considered while repurposing drugs for GBM.

SARS-CoV-2-host proteome interactions for antiviral drug discovery

Treatment options for COVID-19, caused by SARS-CoV-2, remain limited. Understanding viral pathogenesis at the molecular level is critical to develop effective therapy. Some recent studies have explored SARS-CoV-2-host interactomes and provided great resources for understanding viral replication. However, host proteins that functionally associate with SARS-CoV-2 are localized in the corresponding subnetwork within the comprehensive human interactome. Therefore, constructing a downstream network including all potential viral receptors, host cell proteases, and cofactors is necessary and should be used as an additional criterion for the validation of critical host machineries used for viral processing. This study applied both affinity purification mass spectrometry (AP-MS) and the complementary proximity-based labeling MS method (BioID-MS) on 29 viral ORFs and 18 host proteins with potential roles in viral replication to map the interactions relevant to viral processing. The analysis yields a list of 693 hub proteins sharing interactions with both viral baits and host baits and revealed their biological significance for SARS-CoV-2. Those hub proteins then served as a rational resource for drug repurposing via a virtual screening approach. The overall process resulted in the suggested repurposing of 59 compounds for 15 protein targets. Furthermore, antiviral effects of some candidate drugs were observed in vitro validation using image-based drug screen with infectious SARS-CoV-2. In addition, our results suggest that the antiviral activity of methotrexate could be associated with its inhibitory effect on specific protein-protein interactions.

Translation Initiation Machinery as a Tumor Selective Target for Radiosensitization

Towards improving the efficacy of radiotherapy, one approach is to target the molecules and processes mediating cellular radioresponse. Along these lines, translational control of gene expression has been established as a fundamental component of cellular radioresponse, which suggests that the molecules participating in this process (i.e., the translational machinery) can serve as determinants of radiosensitivity. Moreover, the proteins comprising the translational machinery are often overexpressed in tumor cells suggesting the potential for tumor specific radiosensitization. Studies to date have shown that inhibiting proteins involved in translation initiation, the rate-limiting step in translation, specifically the three members of the eIF4F cap binding complex eIF4E, eIF4G, and eIF4A as well as the cap binding regulatory kinases mTOR and Mnk1/2, results in the radiosensitization of tumor cells. Because ribosomes are required for translation initiation, inhibiting ribosome biogenesis also appears to be a strategy for radiosensitization. In general, the radiosensitization induced by targeting the translation initiation machinery involves inhibition of DNA repair, which appears to be the consequence of a reduced expression of proteins critical to radioresponse. The availability of clinically relevant inhibitors of this component of the translational machinery suggests opportunities to extend this approach to radiosensitization to patient care.

Pharmacological strategies for improving the prognosis of glioblastoma

Introduction: Treatments for brain cancer have radically evolved in the past decade due to a better understanding of the interplay between the immune system and tumors of the central nervous system (CNS). However, glioblastoma multiforme (GBM) remains the most common and lethal CNS malignancy affecting adults.Areas covered: The authors review the literature on glioblastoma pharmacologic therapies with a focus on trials of combination chemo-/immunotherapies and drug delivery platforms from 2015 to 2021.Expert opinion: Few therapeutic advances in GBM treatment have been made since the Food and Drug Administration (FDA) approval of the BCNU-eluting wafer, Gliadel, in 1996 and oral temozolomide (TMZ) in 2005. Recent advances in our understanding of GBM have promoted a wide assortment of new therapeutic approaches including combination therapy, immunotherapy, vaccines, and Car T-cell therapy along with developments in drug delivery. Given promising preclinical data, these novel pharmacotherapies for the treatment of GBM are currently being evaluated in various stages of clinical trials.

Research progress in the application of bile acid-drug conjugates: A "trojan horse" strategy

Bile acid transporters are highly expressed in intestinal cells and hepatocytes, and they determine the uptake of drugs in cells by modulating cellular entry and exit. In order to improve the oral bioavailability of drugs and investigate the potential application prospects of drugs used to target cancer, numerous studies have adopted these transporters to identify prodrug strategies. Through the connection of covalent bonds between drugs and bile acids, the resulting bile acid-drug conjugates continue to be recognized as similar to natural unmodified bile acid and is translocated by the transporter. The present mini-review provides a brief summary of recent progress of the application of bile acid-drug conjugates based primarily on ASBT, NTCP, and OATP, with the hope of contributing to subsequent research.

Reviewing Antiviral Research Against Viruses Causing Human Diseases - A Structure Guided Approach

The littlest of all the pathogens, viruses have continuously been the foremost strange microorganisms to consider. Viral Infections can cause extreme sicknesses as archived by the HIV/AIDS widespread or the later Ebola or Zika episodes. Apprehensive framework distortions are too regularly watched results of numerous viral contaminations. Besides, numerous infections are oncoviruses, which can trigger different sorts of cancer. Nearly every year a modern infection species rises debilitating the world populace with an annihilating episode. Subsequently, the need of creating antivirals to combat such rising infections. In any case, from the innovation of to begin with antiviral medicate Idoxuridine in 1962 to the revelation of Baloxavir marboxil (Xofluza) that was FDA-approved in 2018, the hone of creating antivirals has changed significantly. In this article, different auxiliary science strategies have been described that can be referral for therapeutics innovation.

Host gut microbiome and potential therapeutics in Gulf War Illness: A short review

AIMS

Since our troops had returned from the first Persian Gulf War in 1990-91, the veterans have reported chronic multisymptomatic illness widely referred to as Gulf War Illness (GWI). We aim to review the current directions of GWI pathology research in the context of chronic multisymptomatic illness and its possible gut microbiome targeted therapies. The veterans of Gulf War show symptoms of chronic fatigue, cognitive deficits, and a subsection report of gastrointestinal complications.

METHOD

Efforts of finding a suitable treatment regimen and clinical management remain a challenge. More recently, we have shown that the pathology is connected to alterations in the gut microbiome, and efforts of finding a suitable regimen for gut-directed therapeutics are underway. We discuss the various clinical interventions and summarize the possible effectiveness of gut-directed therapies such as the use of short-chain fatty acids (SCFA), phenolic compounds, and their metabolites, use of probiotics, and fecal microbiota transfer.

SIGNIFICANCE

The short review will be helpful to GWI researchers to expand their studies to the gut and find an effective treatment strategy for chronic multisymptomatic illness.

The Role of RNA Modifications and RNA-modifying Proteins in Cancer Therapy and Drug Resistance

The advent of new genome-wide sequencing technologies has uncovered abnormal RNA modifications and RNA editing in a variety of human cancers. The discovery of reversible RNA N6-methyladenosine (RNA: m⁶A) by fat mass and obesity-associated protein (FTO) demethylase has led to exponential publications on the pathophysiological functions of m⁶A and its corresponding RNA modifying proteins (RMPs) in the past decade. Some excellent reviews have summarized the recent progress in this field. Compared to the extent of research into RNA: m⁶A and DNA 5-methylcytosine (DNA: m⁵C), much less is known about other RNA modifications and their associated RMPs, such as the role of RNA: m⁵C and its RNA cytosine methyltransferases (RCMTs) in cancer therapy and drug resistance. In this review, we will summarize the recent progress surrounding the function, intramolecular distribution and subcellular localization of several major RNA modifications, including 5' cap N7-methylguanosine (m7G) and 2'-O-methylation (Nm), m⁶A, m⁵C, A-to-I editing, and the associated RMPs. We will then discuss dysregulation of those RNA modifications and RMPs in cancer and their role in cancer therapy and drug resistance.

Targeting mTOR and eIF4E: a feasible scenario in ovarian cancer therapy

Ovarian carcinoma is one of the most common causes for cancer death in women; lack of early diagnosis and acquired resistance to platinum-based chemotherapy account for its poor prognosis and high mortality rate. As with other cancer types, ovarian cancer is characterized by dysregulated signaling pathways and protein synthesis, which together contribute to rapid cellular growth and invasiveness. The mechanistic/mammalian target of rapamycin (mTOR) pathway represents the core of different signaling pathways regulating a number of essential steps in the cell, among which protein synthesis and the eukaryotic initiation factor 4E (eIF4E), the mRNA cap binding protein, is one of its downstream effectors. eIF4E is a limiting factor in translation initiation and its overexpression is a hallmark in many cancers. Because its action is regulated by a number of factors that compete for the same binding site, eIF4E is an ideal target for developing novel antineoplastic drugs. Several inhibitors targeting the mTOR signaling pathway have been designed thus far, however most of these molecules show poor stability and high toxicity in vivo. This minireview explores the possibility of targeting mTOR and eIF4E proteins, thus impacting on translation initiation in ovarian cancer, describing the most promising experimental strategies and specific inhibitors that have been shown to have an effect on other kinds of cancers.

Preclinical efficacy of ribavirin in SHH and group 3 medulloblastoma

OBJECTIVE

Medulloblastoma, the most common pediatric brain malignancy, has Sonic Hedgehog (SHH) and group 3 (Myc driven) subtypes that are associated with the activity of eukaryotic initiation factor 4E (eIF4E), a critical mediator of translation, and enhancer of zeste homolog 2 (EZH2), a histone methyltransferase and master regulator of transcription. Recent drug repurposing efforts in multiple solid and hematologic malignancies have demonstrated that eIF4E and EZH2 are both pharmacologically inhibited by the FDA-approved antiviral drug ribavirin. Given the molecular overlap between medulloblastoma biology and known ribavirin activity, the authors investigated the preclinical efficacy of repurposing ribavirin as a targeted therapeutic in cell and animal models of medulloblastoma.

METHODS

Multiple in vitro assays were performed using human ONS-76 (a primitive SHH model) and D425 (an aggressive group 3 model) cells. The impacts of ribavirin on cellular growth, death, migration, and invasion were quantified using proliferation and Cell Counting Kit-8 (CCK-8) assays, flow cytometry with annexin V (AnnV) staining, scratch wound assays, and Matrigel invasion chambers, respectively. Survival following daily ribavirin treatment (100 mg/kg) was assessed in vivo in immunodeficient mice intracranially implanted with D425 cells.

RESULTS

Compared to controls, ribavirin treatment led to a significant reduction in medulloblastoma cell growth (ONS-76 proliferation assay, p = 0.0001; D425 CCK-8 assay, p < 0.0001) and a significant increase in cell death (flow cytometry for AnnV, ONS-76, p = 0.0010; D425, p = 0.0284). In ONS-76 cells, compared to controls, ribavirin significantly decreased cell migration and invasion (Matrigel invasion chamber assay, p = 0.0012). In vivo, ribavirin significantly extended survival in an aggressive group 3 medulloblastoma mouse model compared to vehicle-treated controls (p = 0.0004).

CONCLUSIONS

The authors demonstrate that ribavirin, a clinically used drug known to inhibit eIF4E and EZH2, has significant antitumor effects in multiple preclinical models of medulloblastoma, including an aggressive group 3 animal model. Ribavirin may represent a promising targeted therapeutic in medulloblastoma.

Roles of RNA Methylation on Tumor Immunity and Clinical Implications

RNA methylation is a kind of RNA modification that exists widely in eukaryotes and prokaryotes. RNA methylation occurs not only in mRNA but also in ncRNA. According to the different sites of methylation, RNA methylation includes m⁶A, m⁵C, m⁷G, and 2-O-methylation modifications. Modifications affect the splicing, nucleation, stability and immunogenicity of RNA. RNA methylation is involved in many physiological and pathological processes. In the immune system, especially for tumor immunity, RNA methylation affects the maturation and response function of immune cells. Through the influence of RNA immunogenicity and innate immune components, modifications regulate the innate immunity of the body. Some recent studies verified that RNA methylation can regulate tumor immunity, which also provides a new idea for the future of treating immunological diseases and tumor immunotherapy.

Ribavirin shows antiviral activity against SARS-CoV-2 and downregulates the activity of TMPRSS2 and the expression of ACE2 in vitro

Ribavirin is a guanosine analog with broad-spectrum antiviral activity against RNA viruses. Based on this, we aimed to show the anti-SARS-CoV-2 activity of this drug molecule via in vitro, in silico, and molecular techniques. Ribavirin showed antiviral activity in Vero E6 cells following SARS-CoV-2 infection, whereas the drug itself did not show any toxic effect over the concentration range tested. In silico analysis suggested that ribavirin has a broad-spectrum impact on SARS-CoV-2, acting at different viral proteins. According to the detailed molecular techniques, ribavirin was shown to decrease the expression of TMPRSS2 at both mRNA and protein levels 48 h after treatment. The suppressive effect of ribavirin in ACE2 protein expression was shown to be dependent on cell types. Finally, proteolytic activity assays showed that ribavirin also showed an inhibitory effect on the TMPRSS2 enzyme. Based on these results, we hypothesized that ribavirin may inhibit the expression of TMPRSS2 by modulating the formation of inhibitory G-quadruplex structures at the TMPRSS2 promoter. As a conclusion, ribavirin is a potential antiviral drug for the treatment against SARS-CoV-2, and it interferes with the effects of TMPRSS2 and ACE2 expression.

Inhibitors of Eukaryotic Translational Machinery as Therapeutic Agents

Inhibiting eukaryotic protein translation with small molecules is emerging as a powerful therapeutic strategy. The advantage of targeting cellular translational machinery is that it is required for the highly proliferative state of many neoplastic cells, replication of certain viruses, and ultimately the expression of a wide variety of protein targets. Although, this approach has been exploited to develop clinical agents, such as homoharringtonine (HHT, 1), used to treat chronic myeloid leukemia (CML), inhibiting components of the translational machinery is often associated with cytotoxic phenotypes. However, recent studies have demonstrated that certain small molecules can inhibit the translation of specific subsets of proteins, leading to lower cytotoxicity, and opening-up therapeutic opportunities for translation inhibitors to be deployed in indications beyond oncology and infectious disease. This review summarizes efforts to develop inhibitors of the eukaryotic translational machinery as therapeutic agents and highlights emerging opportunities for translation inhibitors in the future.

Translation initiation in cancer at a glance

Cell division, differentiation and function are largely dependent on accurate proteome composition and regulated gene expression. To control this, protein synthesis is an intricate process governed by upstream signalling pathways. Eukaryotic translation is a multistep process and can be separated into four distinct phases: initiation, elongation, termination and recycling of ribosomal subunits. Translation initiation, the focus of this article, is highly regulated to control the activity and/or function of eukaryotic initiation factors (eIFs) and permit recruitment of mRNAs to the ribosomes. In this Cell Science at a Glance and accompanying poster, we outline the mechanisms by which tumour cells alter the process of translation initiation and discuss how this benefits tumour formation, proliferation and metastasis.

Novel aryltriazole acyclic C-azanucleosides as anticancer candidates

Nucleoside analogues represent an important class of drug candidates. With the aim of searching for novel bioactive nucleosides, we developed an efficient synthetic way to construct a series of aryl 1,2,3-triazole acyclic C-azanucleosides via Huisgen 1,3-dipolar cycloaddition. The aryl 1,2,3-triazole motifs within these azanucleosides showed coplanar features, suggesting they could act as surrogates for large planar aromatic systems or nucleobases. Moreover, several aryltriazole acyclic C-azanucleosides bearing long alkyl chains exhibited potent antiproliferative activity against various cancer cell lines via induction of apoptosis. Most interestingly, the lead compound significantly down-regulated the key proteins involved in the heat shock response pathway, representing the first anticancer acyclic azanucleoside with such a mode of action. These novel aryl 1,2,3-triazole cyclic C-azanucleosides therefore serve as promising paradigms for further exploring anticancer drug candidates.

Repurposing of Kinase Inhibitors for Treatment of COVID-19

The outbreak of COVID-19, the pandemic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spurred an intense search for treatments by the scientific community. In the absence of a vaccine, the goal is to target the viral life cycle and alleviate the lung-damaging symptoms of infection, which can be life-threatening. There are numerous protein kinases associated with these processes that can be inhibited by FDA-approved drugs, the repurposing of which presents an alluring option as they have been thoroughly vetted for safety and are more readily available for treatment of patients and testing in clinical trials. Here, we characterize more than 30 approved kinase inhibitors in terms of their antiviral potential, due to their measured potency against key kinases required for viral entry, metabolism, or reproduction. We also highlight inhibitors with potential to reverse pulmonary insufficiency because of their anti-inflammatory activity, cytokine suppression, or antifibrotic activity. Certain agents are projected to be dual-purpose drugs in terms of antiviral activity and alleviation of disease symptoms, however drug combination is also an option for inhibitors with optimal pharmacokinetic properties that allow safe and efficacious co-administration with other drugs, such as antiviral agents, IL-6 blocking agents, or other kinase inhibitors.

Repurposing the FDA-Approved Antiviral Drug Ribavirin as Targeted Therapy for Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a squamous cell carcinoma with a proclivity for systemic dissemination, leading many patients to present with advanced stage disease and fail available treatments. There is a notable lack of targeted therapies for NPC, despite working knowledge of multiple proteins with integral roles in NPC cancer biology. These proteins include EZH2, Snail, eIF4E, and IMPDH, which are all overexpressed in NPC and correlated with poor prognosis. These proteins are known to be modulated by ribavirin, an FDA-approved hepatitis C antiviral that has recently been repurposed as a promising therapeutic in several solid and hematologic malignancies. Here, we investigated the potential of ribavirin as a targeted anticancer agent in five human NPC cell lines. Using cellular growth assays, flow cytometry, BrdU cell proliferation assays, scratch wound assays, and invasion assays, we show in vitro that ribavirin decreases NPC cellular proliferation, migration, and invasion and promotes cell-cycle arrest and cell death. Modulation of EZH2, Snail, eIF4E, IMPDH, mTOR, and cyclin D1 were observed in Western blots and enzymatic activity assays in response to ribavirin treatment. As monotherapy, ribavirin reduced flank tumor growth in multiple NPC xenograft models in vivo Most importantly, we demonstrate that ribavirin enhanced the effects of radiotherapy, a central component of NPC treatment, both in vitro and in vivo Our work suggests that NPC responds to ribavirin-mediated EZH2, Snail, eIF4E, IMPDH, and mTOR changes and positions ribavirin for clinical evaluation as a potential addition to our NPC treatment armamentarium.

Drug repurposing against COVID-19: focus on anticancer agents

Background

The very limited time allowed to face the COVID-19 pandemic poses a pressing challenge to find proper therapeutic approaches. However, synthesis and full investigation from preclinical studies to phase III trials of new medications is a time-consuming procedure, and not viable in a global emergency, such as the one we are facing.

Main Body

Drug repurposing/repositioning, a strategy effectively employed in cancer treatment, can represent a valid alternative. Most drugs considered for repurposing/repositioning in the therapy of the COVID-19 outbreak are commercially available and their dosage and toxicity in humans is well known, due to years (or even decades) of clinical use. This can allow their fast-track evaluation in phase II–III clinical trials, or even within straightforward compassionate use.

Several drugs being re-considered for COVID-19 therapy are or have been used in cancer therapy. Indeed, virus-infected cells are pushed to enhance the synthesis of nucleic acids, protein and lipid synthesis and boost their energy metabolism, in order to comply to the “viral program”. Indeed, the same features are seen in cancer cells, making it likely that drugs interfering with specific cancer cell pathways may be effective as well in defeating viral replication.

Short Conclusion

To our knowledge, cancer drugs potentially suitable for facing SARS-CoV-2 infection have not been carefully reviewed. We present here a comprehensive analysis of available information on potential candidate cancer drugs that can be repurposed for the treatment of COIVD-19.

Novel triazole nucleoside analogues promote anticancer activity via both apoptosis and autophagy

Novel triazole nucleosides developed by the strategy of “terminal N,N-dimethylation” displayed anticancer activity mediated via apoptosis and autophagy.

Critical View on the Usage of Ribavirin in Already Existing Psychostimulant-Use Disorder

Substance-use disorder represents a frequently hidden non-communicable chronic disease. Patients with intravenous drug addiction are at high risk of direct exposure to a variety of viral infections and are considered to be the largest subpopulation infected with the hepatitis C virus. Ribavirin is a synthetic nucleoside analog that has been used as an integral component of hepatitis C therapy. However, ribavirin medication is quite often associated with pronounced psychiatric adverse effects. It is not well understood to what extent ribavirin per se contributes to changes in drug-related neurobehavioral disturbances, especially in the case of psychostimulant drugs, such as amphetamine. It is now well-known that repeated amphetamine usage produces psychosis in humans and behavioral sensitization in animals. On the other hand, ribavirin has an affinity for adenosine A1 receptors that antagonistically modulate the activity of dopamine D1 receptors, which play a critical role in the development of behavioral sensitization. This review will focus on the current knowledge of neurochemical/ neurobiological changes that exist in the psychostimulant drug-addicted brain itself and the antipsychotic-like efficiency of adenosine agonists. Particular attention will be paid to the potential side effects of ribavirin therapy, and the opportunities and challenges related to its application in already existing psychostimulant-use disorder.

Drug repurposing for cancer therapy, easier said than done

Drug repurposing for cancer therapy is currently a hot topic of research. Theoretically, in contrast to the known hurdles of developing new molecular entities, the approach of repurposing has several advantages. Mostly, it is said that it is faster, safer, easier, and cheaper. In the real world, however, there are only three repurposed drugs so far, that are listed in widely recognized cancer guidelines, but a large number of them are being studied. Among the many barriers to repurposing cancer drugs, economical-driven are the most important that difficult the clinical development of them. In this review, we provide an overview of the current status of drug repurposing for cancer therapy and the barriers that need to be overcome to realize the benefit of this approach. It means to have repositioned drugs for cancer therapy accepted as standard therapy for cancer indications at low cost.

Synthesis and antitumor activities investigation of a C-nucleoside analogue of ribavirin

SRO-91 is a non-natural ribofuranosyl-1,2,3-triazole C-nucleoside obtained by a synthetic sequence involving a C-alkynyl glycosylation mediated by metallic indium and a Huisgen cycloaddition for the construction of the triazole. Its structure is close to the one of ribavirin, a drug presenting a broad-spectrum against viral infections. SRO-91 antitumor activities were investigated on 9 strains of tumor cells and IC₅₀ of the order of 1 μM were obtained on A431 epidermoid carcinoma cells and B16F10 skin melanoma cells. In addition, studies of ovarian tumor cell inhibitions show an interesting activity in regard to the need for new drugs for this pathology. Finally, cytotoxicity and mouse toxicity studies reveal a favorable therapeutic index for SRO-91.