Adenosine Analogues Research Articles

Tubercidin inhibits PRRSV replication via RIG-I/NF-κB pathways and interrupting viral nsp2 synthesis.

Porcine reproductive and respiratory syndrome (PRRS) is one of the most important swine diseases, which causes huge economic loss worldwide. However, there is no effective therapeutic method for PRRS prevention and control. Here, we found that tubercidin, a naturally extracted adenosine analog, exhibited strong anti-porcine reproductive and respiratory syndrome virus (PRRSV) activity. Mechanically, tubercidin inhibited viral binding, replication, and release. Tubercidin suppressed PRRSV non-structural protein 2 expression, which is important for the formation of replication and transcription complex, leading to the block of viral RNA synthesis and PRRSV replication. Moreover, tubercidin could activate retinoic acid-inducible gene I/nuclear factor kappa-light-chain-enhancer of activated B cell innate immune signaling pathway and increased the expression of interferons and proinflammatory cytokines, which was the other way to inhibit PRRSV replication. Our work evaluated the potential value of tubercidin as an antiviral agent on PRRSV replication and provided a new way to prevent PRRSV replication in vitro.

Enhanced TROSY Effect in [2‐19F, 2‐13C] Adenosine and ATP Analogs Facilitates NMR Spectroscopy of Very Large Biological RNAs in Solution

AbstractLarge RNAs are central to cellular functions, but characterizing such RNAs remains challenging by solution NMR. We present two labeling technologies based on [2‐19F, 2‐13C]‐adenosine, which allow the incorporation of aromatic 19F‐13C spin pairs. The labels when coupled with the transverse relaxation optimized spectroscopy (TROSY) enable us to probe RNAs comprising up to 124 nucleotides. With our new [2‐19F, 2‐13C]‐adenosine‐phosphoramidite, all resonances of the human hepatitis B virus epsilon RNA could be readily assigned. With [2‐19F, 2‐13C]‐adenosine triphosphate, the 124 nt pre‐miR‐17‐NPSL1‐RNA was produced via in vitro transcription and the TROSY spectrum of this 40 kDa [2‐19F, 2‐13C]‐A‐labeled RNA featured sharper resonances than the [2‐1H, 2‐13C]‐A sample. The mutual cancelation of the chemical‐shift‐anisotropy and the dipole‐dipole‐components of TROSY‐resonances leads to narrow linewidths over a wide range of molecular weights. With the synthesis of a non‐hydrolysable [2‐19F, 2‐13C]‐adenosine‐triphosphate, we facilitate the probing of co‐factor binding in kinase complexes and NMR‐based inhibitor binding studies in such systems. Our labels allow a straightforward assignment for larger RNAs via a divide‐and‐conquer/mutational approach. The new [2‐19F, 2‐13C]‐adenosine precursors are a valuable addition to the RNA NMR toolbox and will allow the study of large RNAs/RNA protein complexes in vitro and in cells.

Enhanced TROSY Effect in [2-19 F, 2-13 C] Adenosine and ATP Analogs Facilitates NMR Spectroscopy of Very Large Biological RNAs in Solution.

Large RNAs are central to cellular functions, but characterizing such RNAs remains challenging by solution NMR. We present two labeling technologies based on [2-19 F, 2-13 C]-adenosine, which allow the incorporation of aromatic 19 F-13 C spin pairs. The labels when coupled with the transverse relaxation optimized spectroscopy (TROSY) enable us to probe RNAs comprising up to 124 nucleotides. With our new [2-19 F, 2-13 C]-adenosine-phosphoramidite, all resonances of the human hepatitis B virus epsilon RNA could be readily assigned. With [2-19 F, 2-13 C]-adenosine triphosphate, the 124 nt pre-miR-17-NPSL1-RNA was produced via in vitro transcription and the TROSY spectrum of this 40 kDa [2-19 F, 2-13 C]-A-labeled RNA featured sharper resonances than the [2-1 H, 2-13 C]-A sample. The mutual cancelation of the chemical-shift-anisotropy and the dipole-dipole-components of TROSY-resonances leads to narrow linewidths over a wide range of molecular weights. With the synthesis of a non-hydrolysable [2-19 F, 2-13 C]-adenosine-triphosphate, we facilitate the probing of co-factor binding in kinase complexes and NMR-based inhibitor binding studies in such systems. Our labels allow a straightforward assignment for larger RNAs via a divide-and-conquer/mutational approach. The new [2-19 F, 2-13 C]-adenosine precursors are a valuable addition to the RNA NMR toolbox and will allow the study of large RNAs/RNA protein complexes in vitro and in cells.

The IL-4/13-induced production of M2 chemokines by human lung macrophages is enhanced by adenosine and PGE2

Background and purposeLung macrophages (LMs) are critically involved in respiratory diseases. The primary objective of the present study was to determine whether or not an adenosine analog (NECA) and prostaglandin E2 (PGE2) affected the interleukin (IL)-4- and IL-13-induced release of M2a chemokines (CCL13, CCL17, CCL18, and CCL22) by human LMs. Experimental ApproachPrimary macrophages isolated from resected human lungs were incubated with NECA, PGE2, roflumilast, or vehicle and stimulated with IL-4 or IL-13 for 24 h. The levels of chemokines and PGE2 in the culture supernatants were measured using ELISAs and enzyme immunoassays. Key resultsExposure to IL-4 (10 ng/mL) and IL-13 (50 ng/mL) was associated with greater M2a chemokine production but not PGE2 production. PGE2 (10 ng/mL) and NECA (10-6 M) induced the production of M2a chemokines to a lesser extent but significantly enhanced the IL-4/IL-13-induced production of these chemokines. At either a clinically relevant concentration (10-9 M) or at a concentration (10-7 M) that fully inhibited phosphodiesterase 4 (PDE4) activity, roflumilast did not increase the production of M2a chemokines and did not modulate their IL-13-induced production, regardless of the presence or absence of PGE2. ConclusionsNECA and PGE2 enhanced the IL-4/IL-13-induced production of M2a chemokines. The inhibition of PDE4 by roflumilast did not alter the production of these chemokines. These results contrast totally with the previously reported inhibitory effects of NECA, PGE2, and PDE4 inhibitors on the lipopolysaccharide-induced release of tumor necrosis factor alpha and M1 chemokines in human LMs.

Evaluation of ENG/CD105 expression, methylation, immuno-response, and cordycepin (CD) regulation as a novel biomarker of breast invasive carcinoma (BRCA).

ENG/CD105 encodes a vascular endothelial glycoprotein and plays a crucial role in modulating angiogenesis. However, the significance of ENG expression, DNA methylation, immuno-response, and cordycepin (CD) regulation as diagnostic, prognostic, and therapeutic markers for breast invasive carcinoma (BRCA) remains unclear. As a result, ENG is decreased in BRCA tissues compared with corresponding healthy tissues. Five isoforms were found, and the utilization for ENG isoform (ENG-002) was the highest, suggesting its potential involvement in important roles in BRCA. ENG DNA was frequently altered in most types of cancer, and overall survival (OS) for mutant ENG was significantly longer than for wild-type cases. High expressions of ENG remarkably correlate with long relapse-free survival (RFS) for breast cancer (BC). Additionally, the ENG methylation level was higher in BRCA tissues compared with matched healthy tissues. The ENG expression and DNA methylation showed a significantly reverse correlation, demonstrating that ENG methylation may be a regulatory mechanism. By constructing diagnostic and prognostic models of ENG methylation for BRCA, we found four CpGs (CpG sites) that ranked with high importance. High methylation for cg14185922 of ENG in BRCA tissues showed shorter OS (high risk), indicating that ENG CpGs' methylation has potential as a diagnostic and prognostic biomarker for BRCA. Moreover, ENG might be a novel target for tumor immune response and immunotherapy in pancancer, including BC. CD, an adenosine analog and anti-cancer agent, increased ENG levels in a dose-dependent manner in animal models. This suggests that CD repressed BC growth and metastasis, at least partially through increasing the expression of the tumor suppressor gene ENG. Thus, our study successfully evaluated ENG/CD105 expression, DNA methylation, immune response, and CD regulation, which act as a novel diagnostic, prognostic, and therapeutic biomarker for BRCA. This research also fills critical knowledge gaps in this ENG/cancer field and highlights ENG's potential importance for the diagnosis, prognosis, and treatment of BRCA.

Synthesis of acyclic analogues of adenosine sulfonamides and their activity against RNA cap guanine N7-methyltransferase of SARS-CoV-2

Original N-arylsulfonamide acyclic analogues of adenosine as bisubstrates of RNA cap guanine N7-methyltransferase nsp14 of SARS-CoV-2 were prepared and some of them were barely active at 50 μM against this RNA cap methylation enzyme.

Site-specific RNA modification via initiation of in vitro transcription reactions with m6A and isomorphic emissive adenosine analogs.

The templated enzymatic incorporation of adenosine and its analogs, including m6A, thA and tzA into RNA transcripts, has been explored. Enforced transcription initiation with excess free nucleosides and the native triphosphates generates 5'-end modified transcripts, which can be 5'-phosphorylated and ligated to provide full length, singly modified RNA oligomers. To explore structural integrity, functionality and utility of the resulting non-canonical purine-containing RNA constructs, a MazF RNA hairpin substrate has been synthesized and analyzed for its susceptibility to this endonuclease. Additionally, RNA substrates, containing a singly incorporated isomorphic emissive nucleoside, can be used to monitor the enzymatic reactions in real-time by steady state fluorescence spectroscopy.

Cladribine tablets after treatment with natalizumab (CLADRINA) - rationale and design.

Individual disease modifying therapies approved for multiple sclerosis (MS) have limited effectiveness and potentially serious side effects, especially when administered over long periods. Sequential combination therapy is a plausible alternative approach. Natalizumab is a monoclonal therapeutic antibody that reduces leukocyte access to the central nervous system that is associated with an increased risk of progressive multifocal leukoencephalopathy and disease reactivation after its discontinuation. Cladribine tablets act as a synthetic adenosine analog, disrupting DNA synthesis and repair, thereby reducing the number of lymphocytes. The generation of prospective, rigorous safety, and efficacy data in transitioning from natalizumab to cladribine is an unmet clinical need. To test the feasibility of transitioning patients with relapsing forms of MS natalizumab to cladribine tablets. Cladribine tablets after treatment with natalizumab (CLADRINA) is an open-label, single-arm, multicenter, collaborative phase IV, research study that will generate hypothesis regarding the safety, efficacy, and immunological impact of transition from natalizumab to cladribine tablets in patients with relapsing forms of MS. Participants will be recruited from three different sites. The primary endpoint is the absolute and percent change from baseline of lymphocytes and myeloid cell subsets, as well as blood neurofilament light levels. The secondary endpoint is the annualized relapse rate over the 12- and 24-month trial periods. Exploratory endpoints include the expanded disability status scale, and magnetic resonance imaging outcomes. The CLADRINA trial will generate data regarding the safety, efficacy, and immunological impact of the transition from natalizumab to cladribine. As the pace of immunological knowledge of MS continues, insight into disease modifying therapy transition strategies is needed.

N-Arylsulfonamide-based adenosine analogues to target RNA cap N7-methyltransferase nsp14 of SARS-CoV-2.

RNA cap methylations have been shown to be crucial for the life cycle, replication, and infection of ssRNA viruses, as well as for evading the host's innate immune system. Viral methyltransferases (MTases) therefore represent an attractive target for the development of compounds as tools and inhibitors. In coronaviruses, N7-methyltransferase function is localized in nsp14, which has become an increasingly important therapeutic target with the COVID-19 pandemic. In recent years, we have been developing SAH-derived bisubstrates with adenosine and an N-arylsulfonamide moiety targeting both SAM and RNA binding sites in nsp14. We report here the synthesis of 31 SAH analogues with the N-arylsulfonamide attached to the 5'-position of adenosine via different linkers such as N-ethylthioether, N-ethylsulfone, N-ethylamino or N-methyltriazole. The compounds were obtained efficiently by amine sulfonylation or click chemistry. Their ability to inhibit SARS-CoV-2 N7-MTase was evaluated and the best inhibitors showed a submicromolar inhibitory activity against N7-MTase nsp14.

Ab initio Modeling of Hydrogen Bonding of Remdesivir and Adenosine with Uridine.

Remdesivir (RDV) emerged as an effective drug against the SARS-CoV-2 virus pandemic. One of the crucial steps in the mechanism of action of RDV is its incorporation into the growing RNA strand. RDV, an adenosine analogue, forms Watson-Crick (WC) type hydrogen bonds with uridine in the complementary strand and the strength of this interaction will control efficacy of RDV. While there is a plethora of structural and energetic information available about WC H-bonds in natural base pairs, the interaction of RDV with uridine has not been studied yet at the atomic level. In this article, we aim to bridge this gap, to understand RDV and its hydrogen bonding interactions, by employing density functional theory (DFT) at the M06-2X/cc-pVDZ level. The interaction energy, QTAIM analysis, NBO and SAPT2 are performed for RDV, adenosine, and their complex with uridine to gain insights into the nature of hydrogen bonding. The computations show that RDV has similar geometry, energetic, molecular orbitals, and aromaticity as adenosine, suggesting that RDV is an effective adenosine analogue. The important geometrical parameters, such as bond distances and red-shift in the stretching vibrational modes of adenosine, RDV and uridine identify two WC-type H-bonds. The relative strength of these two H-bonds is computed using QTAIM parameters and the computed hydrogen bond energy. Finally, the SAPT2 study is performed at the minima and at non-equilibrium base pair distances to understand the dominant intermolecular physical force. This study, based on a thorough analysis of a variety of computations, suggests that both adenosine and RDV have similar structure, energetic, and hydrogen bonding behaviour.

8-Chloroadenosine Induces ER Stress and Apoptotic Cell Death in Cholangiocarcinoma Cells.

Cholangiocarcinoma is a lethal cancer, and current chemotherapeutic drugs are not very effective. Recent studies reported that cholangiocarcinoma cells were sensitive to adenosine. One adenosine analog, 8-chloroadenosine (8-CA), was shown to be more potent than adenosine and induced apoptosis in leukemia cells. This study examined effects of 8-CA in cholangiocarcinoma cells and immortalized cholangiocytes. Cell growth was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell invasion was examined by transwell assay. Cell cycle and cell death were evaluated by flow cytometry. Colorimetric absorbance assay was used to assessed RNA and protein synthesis as well as mitochondrial membrane potential. Protein levels were examined by western blot analysis. Animal experiment was performed in Balb/cAJcl-Nu mice. 8-CA reduced cholangiocarcinoma cell growth, prevented colony formation and caused endoplasmic reticulum stress and cell-cycle arrest. Eventually, apoptosis was induced. However, treatment with 8-CA did not interfere with RNA synthesis or protein synthesis and did not alter mitochondrial membrane potential. Combination of 8-CA with several chemotherapeutic drugs in vitro was less effective than 8-CA alone and the drugs alone, except for the combination of 8-CA with hydroxychloroquine, which had an additive effect on RMCCA-1 cells. However, further in vivo study showed that treatment with 8-CA alone inhibited tumor growth more than treatment with a combination of 8-CA with hydroxychloroquine. 8-Chloroadenosine inhibited CCA cells by inducing endoplasmic reticulum stress and apoptosis. In vivo study showed that 8-CA inhibited cholangiocarcinoma tumor growth better when administered alone as compared to a combination with hydroxychloroquine.

Synthesis and biological evaluation of Ribo 7-N/O/S pyrimidine 9-deaza C-nucleoside analogs as new antiviral agents for inhibiting HCV RNA-dependent RNA polymerases

Hepatitis C infection is caused by the bloodborne pathogen hepatitis C virus (HCV) and can lead to serious liver diseases and, ultimately, death if the treatment is ineffective. This work reports the synthesis and preclinical evaluation of 7 novel 9-O/N/S pyrimidine nucleosides, including compound 12, the triphosphate of known compound 7b. The nucleosides are 9-deaza modifications of adenosine and guanosine with β-2′-C-methyl substituent on the ribose. Within this series of compounds, a 9-deaza furopyrimidine analog of adenosine, compound 7b, showed high anti-HCV activity in vitro, good stability, low toxicity, and low genotoxicity when administrated in low doses, and an adequate pharmacokinetics profile. An improved synthesis of compound 7b compared to a previous study is also reported. Compound 12 was synthesized as a control to verify phosphorylation of 7b occurred in vivo.

In vitro activity of tubercidin against Mycobacterium tuberculosis and nontuberculosis Mycobacteria.

Tubercidin is an adenosine analogue that has been shown to exhibit good activity against some tumours and parasites. In this study, the in vitro activity of tubercidin was evaluated against Mycobacterium tuberculosis (Mtb) and nontuberculosis Mycobacteria (NTM). For determining the MICs of tubercidin, 23 fully drug-sensitive (DS) Mtb strains, 33 multi-drug resistance tuberculosis (MDR-TB) strains, 29 pre-extensively drug-resistant tuberculosis (pre-XDR-TB) strains, 21 extensively drug-resistant tuberculosis (XDR-TB) strains, 17 rapidly growing mycobacteria (RGM) and nine slowly growing mycobacteria (SGM) references strains were tested by microplate-based Alamar Blue assay (MABA) method. The results indicate that tubercidin has high in vitro activity against some drug-resistance Mtb strains and NTM reference strains, which warrants further investigation on the actions of tubercidin and its derivatives as potential drugs for mycobacterial infections.

A Facile Synthesis of 3′-Fluoro Hexitol Adenosine and Guanosine Phosphoramidites

AbstractWe report a convenient and scalable synthetic approach for the synthesis of 3′-fluoro hexitol adenosine and guanosine nucleoside analogues and corresponding phosphoramidites in good yield. 1,5-Anhydro-4,6-O-benzylidene-d-glucitol was converted into 1,5-anhydro-4,6-O-benzylidene-3-deoxy-3-fluoro-2-O-trifluoromethanesulfonyl-d-altritol in a three-step process. Glycosylation using adenosine or 2-amino-6-iodopurine yielded the corresponding nucleoside analogues in excellent yield. Based on this strategy, a highly concise and scalable synthesis of 3′-fluoro hexitol purine nucleosides (1–2 g, 18–21% overall yield) was accomplished, which will enable the use of 3′-fluoro hexitol nucleic acids for genetic medicine development and diagnostic applications.

Remdesivir increases mtDNA copy number causing mild alterations to oxidative phosphorylation

SARS-CoV-2 causes the severe respiratory disease COVID-19. Remdesivir (RDV) was the first fast-tracked FDA approved treatment drug for COVID-19. RDV acts as an antiviral ribonucleoside (adenosine) analogue that becomes active once it accumulates intracellularly. It then diffuses into the host cell and terminates viral RNA transcription. Previous studies have shown that certain nucleoside analogues unintentionally inhibit mitochondrial RNA or DNA polymerases or cause mutational changes to mitochondrial DNA (mtDNA). These past findings on the mitochondrial toxicity of ribonucleoside analogues motivated us to investigate what effects RDV may have on mitochondrial function. Using in vitro and in vivo rodent models treated with RDV, we observed increases in mtDNA copy number in Mv1Lu cells (35.26% increase ± 11.33%) and liver (100.27% increase ± 32.73%) upon treatment. However, these increases only resulted in mild changes to mitochondrial function. Surprisingly, skeletal muscle and heart were extremely resistant to RDV treatment, tissues that have preferentially been affected by other nucleoside analogues. Although our data suggest that RDV does not greatly impact mitochondrial function, these data are insightful for the treatment of RDV for individuals with mitochondrial disease.

Relief of Morphine Withdrawal Symptoms by Japanese Sake Yeast Supplement (Saccharomyces cerevisiae sake) Through Adenosine A1 Receptor Activation in Mice

Background: Morphine withdrawal syndrome is often treated with chemical drugs; however, these drugs can have concerning side effects. Some natural substances might offer safer alternatives for managing withdrawal symptoms. The neuroprotective activity of the adenosine A1 receptor (A1R) in the central nervous system (CNS) has been mentioned before. As a novel natural agent, Japanese sake yeast is enriched with adenosine analogs. Objectives: As the first report, the present study was designed to evaluate the effects of the Japanese sake yeast supplement against the excitatory signs of morphine withdrawal syndrome in mice. Methods: Mice were treated orally (gavage) with sake yeast at doses of 100, 200, and 300 mg kg-1 once daily for a week. Furthermore, during the last 3 days of receiving sake yeast, the animals were made physically dependent on morphine by being given twice-daily subcutaneous injections of increasing doses of morphine (30 - 90 mg/kg) for 3 consecutive days. The withdrawal syndrome was induced in animals through the intraperitoneal (i.p.) administration of naloxone (3 mg kg-1) or was elicited spontaneously. After the examination of withdrawal signs, the animals were decapitated, and their brains were prepared for histopathology. Results: Sake yeast alleviated the intensity of ptosis, piloerection, diarrhea, irritability, and tremor during the two withdrawal syndrome protocols (P

Structure-Activity Relationship of Truncated 2,8-Disubstituted-Adenosine Derivatives as Dual A2A/A3 Adenosine Receptor Antagonists and Their Cancer Immunotherapeutic Activity.

Based on hA2AAR structures, a hydrophobic C8-heteroaromatic ring in 5'-truncated adenosine analogues occupies the subpocket tightly, converting hA2AAR agonists into antagonists while maintaining affinity toward hA3AR. The final compounds of 2,8-disubstituted-N6-substituted 4'-thionucleosides, or 4'-oxo, were synthesized from d-mannose and d-erythrono-1,4-lactone, respectively, using a Pd-catalyst-controlled regioselective cross-coupling reaction. All tested compounds completely antagonized hA2AAR, including 5d with the highest affinity (Ki,A2A = 7.7 ± 0.5 nM). The hA2AAR-5d X-ray structure revealed that C8-heteroaromatic rings prevented receptor activation-associated conformational changes. However, the C8-substituted compounds still antagonized hA3AR. Structural SAR features and docking studies supported different binding modes at A2AAR and A3AR, elucidating pharmacophores for receptor activation and selectivity. Favorable pharmacokinetics were demonstrated, in which 5d displayed high oral absorption, moderate half-life, and bioavailability. Also, 5d significantly improved the antitumor effect of anti-PD-L1 in vivo. Overall, this study suggests that the novel dual A2AAR/A3AR nucleoside antagonists would be promising drug candidates for immune-oncology.

Quantification of GS-441524 concentration in feline plasma using high performance liquid chromatography with fluorescence detection

The adenosine analogue GS-441524 has demonstrated efficacy in treatment of feline infectious peritonitis (FIP). With no commercially registered formulations of GS-441524 available, global focus shifted to its pro-drug remdesivir, as it became more accessible throughout the COVID-19 pandemic. This study developed and validated a simple liquid chromatography equipped with a fluorescence detector to quantify plasma concentrations of GS-441524 applicable for routine therapeutic monitoring of remdesivir or GS-441524 therapy for FIP infected cats. A Waters X-Bridge C18, 5 µm, 150 × 4.6 mm, column was used and mixtures of 20 mM ammonium acetate (pH 4.5) with acetonitrile of 5% and 70% were prepared for gradient mobile phase. With a simple protein precipitation using methanol to clean plasma sample, GS-441524 was monitored at excitation and emission wavelengths of 250 nm and 475 nm, respectively. Using an external standard, the lowest and highest limits of quantification were 19.5 ng/mL to 10,000 ng/mL, respectively. The intra- and inter day trueness of the quality controls (QCs) were within 10% of their nominal concentrations and intra- and inter day precision of the QCs (expressed as the coefficient of variation) ranged from 1.7 to 5.7%, This assay was able to quantify plasma trough levels of GS-441524 (23.7–190.1 ng/mL) after the administration of remdesivir (9.9–15.0 mg/kg BW, IV or SC) in FIP cats (n = 12). Accordingly, this study generated an alternative and cost-effective way to quantify GS-441524 in feline biological fluids at least up to 24 hr after administrations of remdesivir.

“Eritadenine as a regulator of anxiety Disorders: An experimental and docking Approach”

Uncertainty persists regarding the specific chemical causal factors and their corresponding behavioral effects in anxiety disorders. Commonly employed first-line treatments for anxiety target G protein-coupled receptors (GPCRs), including inhibitors of monoaminergic systems. Alternatively, emerging natural bioactive strategies offer potential for mitigating adverse effects. Recent investigations have implicated adenosine in anxiety-triggering mechanisms, while eritadenine, an adenosine analog derived from Shiitake mushroom, has displayed promising attributes. This study explores eritadenine's potential as a bioactive substance for anxiety disorders in mice, employing behavioral tests, pentobarbital-sleep induction, and molecular docking. Behavioral test results reveal a pronounced anxiolytic and sedative-hypnotic pharmacological effect of eritadenine. Our findings suggest that eritadenine may modulate locomotor functions mediated by adenosine receptors, with a stronger affinity for binding to A2AAR over A1AR, thus eliciting these effects.

Cordycepin (3'dA) Induces Cell Death of AC133+ Leukemia Cells via Re-Expression of WIF1 and Down-Modulation of MYC.

Wnt/β-catenin signaling is critically required for the development and maintenance of leukemia stem cells (LSCs) in acute myeloid leukemia (AML) by constitutive activation of myeloid regeneration-related pathways. Cell-intrinsic activation of canonical Wnt signaling propagates in the nucleus by β-catenin translocation, where it induces expression of target oncogenes such as JUN, MYC and CCND1. As the Wnt/β-catenin pathway is now well established to be a key oncogenic signaling pathway promoting leukemic myelopoiesis, targeting it would be an effective strategy to impair LSC functionality. Although the effects of the adenosine analogue cordycepin in repressing β-catenins and destabilizing the LSC niche have been highlighted, the cellular and molecular effects on AML-LSC have not been fully clarified. In the present study, we evaluated the potency and efficacy of cordycepin, a selective repressor of Wnt/β-catenin signaling with anti-leukemia properties, on the AC133+ LSC fraction. Cordycepin effectively reduces cell viability of the AC133+ LSCs in the MUTZ-2 cell model and patient-derived cells through the induction of apoptosis. By Wnt-targeted RNA sequencing panel, we highlighted the re-expression of WIF1 and DKK1 among others, and the consequent downregulation of MYC and PROM1 (CD133) following MUTZ-2 cell exposure to increasing doses of cordycepin. Our results provide new insights into the molecular circuits involved in pharmacological inhibition mediated by cordycepin reinforcing the potential of targeting the Wnt/β-catenin and co-regulatory complexes in AML.