ß-d-N4-hydroxycytidine, a metabolite of molnupiravir, exhibits in vitro antiviral activity against rabies virus.

Rabies is a fatal neurological disorder caused by rabies virus (RABV) infection. Approximately 60,000 patients die from rabies annually, and there are no effective treatments for this disease. Nucleoside analogs are employed as antiviral drugs based on their broad antiviral spectrum, and certain nucleoside analogs have been reported to exhibit anti-RABV activity. The nucleoside analog ß-d-N4-hydroxycytidine (NHC) has antiviral effects against a range of RNA viruses. Molnupiravir (MPV), a prodrug of NHC, is clinically used as an oral antiviral drug for coronavirus infections. Despite its broad-spectrum activity, the antiviral activity of NHC against RABV remains unclear. In this study, we reveal that NHC exhibits comparable in vitro anti-RABV activity as ribavirin and favipiravir (also known as T-705) with a 90% effective concentration of 6 µM in mouse neuroblastoma cells. NHC reduced viral loads in neuronal and nonneuronal cells in a dose-dependent manner. Both laboratory and field RABVs (fixed and street strains, respectively) were susceptible to NHC. However, no increase in survival or reduction in viral titers in the brain was observed in RABV-infected mice treated prophylactically with MPV. These findings highlight the potential and challenges of NHC in the treatment of RABV infection.

Progress on the Synthesis Pathways and Pharmacological Effects of Naturally Occurring Pyrazines.

As one of the most essential types of heterocyclic compounds, pyrazines have a characteristic smell and taste and have a wide range of commercial applications, especially in the food industry. With the development of the food industry, the demand for pyrazines has increased. Therefore, understanding the properties, functions, and synthetic pathways of pyrazines is one of the fundamental methods to produce, control, and apply pyrazines in food or medical systems. In this review, we provide an overview of the synthesis pathways and physiological or pharmacological functions of naturally occurring pyrazines. In particular, we focus on the biosynthesis and pharmacological effects of 2,3,5,6-Tetramethylpyrazine (TTMP), 2,5-Dimethylpyrazine (2,5-DMP), and 2,3,5-trimethylpyrazine (TMP). Furthermore, areas where further research on pyrazines is needed are discussed in this work.

Discovery of Pyrazolopyrazines as Selective, Potent, and Mutant-Active MET Inhibitors with Intracranial Efficacy.

Mesenchymal-epithelial transition factor (MET) is a receptor tyrosine kinase that serves a critical function in numerous developmental, morphogenic, and proliferative signaling pathways. If dysregulated, MET has been shown to be involved in the development and survival of several cancers, including non-small cell lung cancer (NSCLC), renal cancer, and other epithelial tumors. Currently, the clinical efficacy of FDA approved MET inhibitors is limited by on-target acquired resistance, dose-limiting toxicities, and less than optimal efficacy against brain metastasis. Therefore, there is still an unmet medical need for the development of MET inhibitors to address these issues. Herein we report the application of structure-based design for the discovery and development of a novel class of brain-penetrant MET inhibitors with enhanced activity against clinically relevant mutations and improved selectivity. Compound 13 with a MET D1228N cell line IC50 value of 23 nM showed good efficacy in an intracranial tumor model and increased the median overall survival of the animals to 100% when dosed orally at 100 mg/kg daily for 21 days.

Tetramethylpyrazine ameliorates LPS-induced acute lung injury via the miR-369-3p/DSTN axis.

Acute lung injury (ALI) is a severe clinical respiratory condition characterized by high rates of mortality and morbidity, for which effective treatments are currently lacking. In this study, lipopolysaccharide (LPS) was used to induce ALI mice, demonstrating the efficacy of tetramethylpyrazine (TMP) in ameliorating ALI. Subsequent we perfored high-throughput sequencing analysis and used Targetscan 8.0 and miRWalk 3.0 databases to predict the interaction between microRNAs and destrin (DSTN), ultimately identifying miR-369-3p as the focus of the investigation. The adenovirus carrying miR-369-3p was administered one week prior to LPS-induced in order to assess its potential efficacy in ameliorating ALI in mice. The findings indicated that the overexpression of miR-369-3p resulted in enhanced lung function, reduced pulmonary edema, inflammation, and permeability in LPS-induced ALI mice, while the suppression of miR-369-3p exacerbated the damage in these mice. Furthermore, the beneficial effects of TMP on LPS-induced ALI were negated by the downregulation of miR-369-3p. The results of our study demonstrate that TMP mitigates LPS-induced ALI through upregulation of miR-369-3p. Consequently, the findings of this study advocate for the clinical utilization of TMP in ALI treatment, with miR-369-3p emerging as a promising target for future ALI interventions.

The effect of favipiravir on fracture healing.

The aim of this study was to evaluate the effects of favipiravir on fracture healing. Forty-eight female rats which had a femur fracture with intramedullary Kirschner wire fixation performed were divided into 6 groups; 2 control groups (C1, C2) and 4 experimental groups (F1, F2, F3, F4). The control groups (C1, C2) received physiological saline by oral gavage for 14 days. Two of the experimental groups (F1, F2) received favipiravir by oral gavage for 5 days, whereas the other groups (F3, F4) received it for 14 days. C1, F1 and F3 groups were sacrificed and evaluated on the 14th day, and C2, F2 and F4 groups were sacrificed and evaluated on the 28th day. The fracture sites were assessed for healing radiologically using the Lane and Sandhu scoring system, and assessed histologically using the Huo et al. scoring system. There was no difference between the groups regarding radiological and histological evaluations made on the 14th day (P > .05, P=.216, respectively). On the 28th day, the radiological scores were found to be significantly higher in the control group when compared to the experimental groups (P < .05). Histologically, the control group demonstrated better fracture healing than the groups that had favipiravir administered (P < .001). This study has shown that favipiravir can have negative effects on fracture healing both radiologically and histologically.

PTEN Depletion Increases Radiosensitivity in Response to Ataxia Telangiectasia-Related-3 (ATR) Inhibition in Non-Small Cell Lung Cancer (NSCLC).

Radiotherapy (RT) treatment is an important strategy for the management of non-small cell lung cancer (NSCLC). Local recurrence amongst patients with late-stage NSCLC remains a challenge. The loss of PTEN has been associated with radio-resistance. This study aimed to examine the efficacy of RT combined with ataxia telangiectasia-mutated Rad3-related (ATR) inhibition using Ceralasertib in phosphatase and tensin homolog (PTEN)-depleted NSCLC cells and to assess early inflammatory responses indicative of radiation pneumonitis (RP) after combined-modality treatment. Small hairpin RNA (shRNA) transfections were used to generate H460 and A549 PTEN-depleted models. Ceralasertib was evaluated as a single agent and in combination with RT in vitro and in vivo. Histological staining was used to assess immune cell infiltration in pneumonitis-prone C3H/NeJ mice. Here, we report that the inhibition of ATR in combination with RT caused a significant reduction in PTEN-depleted NSCLC cells, with delayed DNA repair and reduced cell viability, as shown by an increase in cells in Sub G1. Combination treatment in vivo significantly inhibited H460 PTEN-depleted tumour growth in comparison to H460 non-targeting PTEN-expressing (NT) cell-line-derived xenografts (CDXs). Additionally, there was no significant increase in infiltrating macrophages or neutrophils except at 4 weeks, whereby combination treatment significantly increased macrophage levels relative to RT alone. Overall, our study demonstrates that ceralasertib and RT combined preferentially sensitises PTEN-depleted NSCLC models in vitro and in vivo, with no impact on early inflammatory response indicative of RP. These findings provide a rationale for evaluating ATR inhibition in combination with RT in NSCLC patients with PTEN mutations.

Covalent Organic Framework-Based Theranostic Platforms for Restricting H1N1 Influenza Virus Infection.

Background: Influenza A (H1N1) virus is a highly contagious respiratory disease that causes severe illness and death. Vaccines and antiviral drugs are limited by viral variation and drug resistance, so developing efficient integrated theranostic options appears significant in anti-influenza virus infection. Methods: In this study, we designed and fabricated covalent organic framework (COF) based theranostic platforms (T705@DATA-COF-Pro), which was composed of an RNA polymerase inhibitor (favipiravir, T705), the carboxyl-enriched COF (DATA-COF) nano-carrier and Cy3-labeled single DNA (ssDNA) probe. Results: The multi-porosity COF core provided an excellent micro-environment and smooth delivery for T705. The ssDNA probe coating bound to the nucleic acids of H1N1 selectively, thus controlling drug release and allowing fluorescence imaging. The combination of COF and probe triggered the synergism, promoting drug further therapeutic outcomes. With the aid of T705@DATA-COF-Pro platforms, the H1N1-infected mouse models lightly achieved diagnosis and significantly prolonged survival. Conclusion: This research underscores the distinctive benefits and immense potential of COF materials in nano-preparations for virus infection, offering novel avenues for the detection and treatment of H1N1 virus infection.

Structural Diversification of Pyrazinone Metabolites via Spontaneous Oxa-Michael Addition in Staphylococcus xylosus.

A family of pyrazinone metabolites (1-11) were characterized from Staphylococcus xylosus ATCC 29971. Six of them were hydroxylated or methoxylated, which were proposed to be produced by the rare noncatalytic oxa-Michael addition reaction with a water or methanol molecule. It was confirmed that isopropyl alcohol can also be the Michael donor of the reaction. 1-7 and the synthetic precursor 2a showed significant inhibition of breast cancer cell migration.

Gynecologic Cancer InterGroup CA125 response has a high negative predictive value for CHK1 inhibitor RECIST response in recurrent ovarian cancer.

We investigated the association of CA125 response with prognosis and RECIST response/progressive disease (PD) criteria in recurrent high grade serous ovarian cancer (HGSOC) patients treated with a cell cycle checkpoint kinase 1 inhibitor (CHK1i), prexasertib. 81 patients had measurable disease per RECISTv1.1, of which 72 and 70 were measurable by Gynecologic Cancer InterGroup (GCIG) CA125 response and PD criteria, respectively. Univariate and multivariate analyses showed that GCIG CA125 response (n = 32) is associated with improved progression-free survival (PFS) and overall survival (OS) compared to no GCIG CA125 response (n = 40) (median PFS 8.0 vs. 3.5 months [HR: 0.30, 95% CI: 0.18-0.51, p < 0.0001]; median OS 19.8 vs. 10.0 months [HR: 0.38, 95% CI: 0.23-0.64, p < 0.001]) independent of BRCA mutation status, platinum-sensitivity, previous PARP inhibitor therapy, ECOG performance status, and FIGO stage. Notably, GCIG CA125 response had a high negative predictive value (NPV: 93%, 95% CI: 80-98), but poor positive predictive value (PPV: 53%, 95% CI: 35-71) in predicting RECIST response. CA125 PD criteria also showed poor concordance with RECIST PD (PPV 56%, 95% CI: 40-71; NPV 33%, 95% CI: 17-54). Therefore, serum CA125 may be useful as a highly accessible prognostic and predictive biomarker to CHK1i therapy in recurrent HGSOC.

Investigation of substituent effects on the electronic structure and antiviral activity of favipiravir derivatives for Covid-19 treatment using DFT and molecular docking.

In this study, Density-functional theory/Time-dependent density-functional theory (DFT/TDDFT) and Molecular docking method was used to investigate the effect of methyl acetate, tetrahydrofuran and cyanobenzylidene substituents on the electronic structure and antiviral activity of favipiravir for treating COVID-19. The DFT and TDDFT computations were employed using the Gaussian 09 software package. The values were calculated using the 6-311++G(d, p) basis set and the hybrid B3LYP functional method. Autodock vina software was used for simulations to better predictions and to validate the modified compounds' binding affinities and poses. Results of the study indicate that compounds 1 to 6 all displayed a planar structure, where the pyrazine ring, carboxamide, hydroxyl groups, and other substituents are all situated within the same plane. In addition, the energy gaps (Egap) of these six compounds (Cpd 1, 2, 3, 4, 5, and 6) were compared. The significant dipole moment and binding affinity achieved implies a particular orientation for binding within the target protein, signaling the anticipated strength of the binding interaction. In all six compounds, the electrophilic domain is situated in the vicinity of the amine functional group within the carboxamide compound, whereas the nucleophilic domain encompasses both the carbonyl and hydroxyl groups. The most negatively charged sites are susceptible to electrophilic interactions. In conclusion, compounds 5 and 6 exhibit a high binding affinity of the target protein, while compound 6 has a high energy gap, which could enhance its antiviral activity against the COVID-19 virus.

Bruton's tyrosine kinase (BTK) inhibitors alter blood glucose and insulin in obese mice but reduce inflammation independent of BTK.

Obesity is associated with metabolic inflammation, which can contribute to insulin resistance, higher blood glucose, and higher insulin indicative of prediabetes progression. The nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a metabolic danger sensor implicated in metabolic inflammation. Many features of metabolic disease can activate the NLRP3 inflammasome; however, it is not yet clear which upstream triggers to target, and there are no clinically approved NLRP3 inflammasome inhibitors for metabolic disease. Bruton's tyrosine kinase (BTK) mediates activation of the NLRP3 inflammasome. Ibrutinib is the most-studied pharmacological inhibitor of BTK, and it can improve blood glucose control in obese mice. However, inhibitors of tyrosine kinases are permissive, and it is unknown if BTK inhibitors require BTK to alter endocrine control of metabolism or metabolic inflammation. We tested whether ibrutinib and acalabrutinib, a new generation BTK inhibitor with higher selectivity, require BTK to inhibit the NLRP3 inflammasome, metabolic inflammation, and blood glucose in obese mice. Chronic ibrutinib administration lowered fasting blood glucose and improved glycemia, whereas acalabrutinib increased fasting insulin levels and increased markers of insulin resistance in high-fat diet-fed CBA/J mice with intact Btk. These metabolic effects of BTK inhibitors were absent in CBA/CaHN-Btkxid/J mice with mutant Btk. However, ibrutinib and acalabrutinib reduced NF-κB activity, proinflammatory gene expression, and NLRP3 inflammasome activation in macrophages with and without functional BTK. These data highlight that the BTK inhibitors can have divergent effects on metabolism and separate effects on metabolic inflammation that can occur independently of actions on BTK.NEW & NOTEWORTHY Bruton's tyrosine kinase (BTK) is involved in immune function. It was thought that BTK inhibitors improve characteristics of obesity-related metabolic disease by lowering metabolic inflammation. However, tyrosine kinase inhibitors are permissive, and it was not known if different BTK inhibitors alter host metabolism or immunity through actions on BTK. We found that two BTK inhibitors had divergent effects on blood glucose and insulin via BTK, but inhibition of metabolic inflammation occurred independently of BTK in obese mice.

Comparative CNS Pharmacology of the Bruton's Tyrosine Kinase (BTK) Inhibitor Tolebrutinib Versus Other BTK Inhibitor Candidates for Treating Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Tolebrutinib is a covalent BTK inhibitor designed and selected for potency and CNS exposure to optimize impact on BTK-dependent signaling in CNS-resident cells. We applied a translational approach to evaluate three BTK inhibitors in Phase 3 clinical development in MS with respect to their relative potency to block BTK-dependent signaling and exposure in the CNS METHODS: We used in vitro kinase and cellular activation assays, alongside pharmacokinetic sampling of cerebrospinal fluid (CSF) in the non-human primate cynomolgus to estimate the ability of these candidates (evobrutinib, fenebrutinib, and tolebrutinib) to block BTK-dependent signaling inside the CNS. RESULTS: In vitro kinase assays demonstrated that tolebrutinib reacted with BTK 65-times faster than evobrutinib, while fenebrutinib, a classical reversible antagonist with a Ki value of 4.7 nM and slow off-rate (1.54 x 10-5 s-1), also had an association rate 1760-fold slower (0.00245 µM-1 * s-1). Estimates of cellular potency were largely consistent with the in vitro kinase assays, with an estimated IC50 of 0.7 nM for tolebrutinib against 33.5 nM for evobrutinib and 2.9 nM for fenebrutinib. We then observed that evobrutinib, fenebrutinib, and tolebrutinib achieved similar levels of exposure in non-human primate CSF after oral doses of 10 mg/kg. However, tolebrutinib CSF exposure (4.8 ng/mL) (kp,uu CSF=0.40) exceeded the IC90 (the estimated concentration inhibiting 90% of kinase activity) value, while evobrutinib (3.2 ng/mL) (kp,uu CSF=0.13) and fenebrutinib (12.9 ng/mL) (kp,uu CSF=0.15) failed to reach the estimated IC90 values. CONCLUSIONS: Tolebrutinib was the only candidate of the three that attained relevant CSF exposure in non-human primates.

Analysis of the susceptibility of refractory hepatitis C virus resistant to nonstructural 5A inhibitors.

Resistance-associated substitutions (RASs) of hepatitis C virus (HCV) affect the efficacy of direct-acting antivirals (DAAs). In this study, we aimed to clarify the susceptibility of the coexistence of nonstructural (NS) 5A Q24K/L28M/R30Q (or R30E)/A92K RASs, which were observed in patients with DAAs re-treatment failure and to consider new therapeutic agents. We used a subgenomic replicon system in which HCV genotype 1B strain 1B-4 was electroporated into OR6c cells derived from HuH-7 cells (Wild-type [WT]). We converted WT genes to NS5A Q24K/L28M/R30Q/A92K or Q24/L28K/R30E/A92K. Compared with the WT, the Q24K/L28M/R30Q/A92K RASs was 36,000-fold resistant to daclatasvir, 440,000-fold resistant to ledipasvir, 6300-fold resistant to velpatasvir, 3100-fold resistant to elbasvir, and 1.8-fold resistant to pibrentasvir. Compared with the WT, the Q24K/L28M/R30E/A92K RASs was 640,000-fold resistant to daclatasvir and ledipasvir, 150,000-fold resistant to velpatasvir, 44,000-fold resistant to elbasvir, and 1500-fold resistant to pibrentasvir. The Q24K/L28M/R30E/A92K RASs was 816.3 times more resistant to pibrentasvir than the Q24K/L28M/R30Q/A92K RASs. Furthermore, a combination of pibrentasvir and sofosbuvir showed therapeutic efficacy against these RASs. Combination regimens may eradicate HCV with NS5A Q24K/L28M/R30E/A92K RASs.

Cephalostatins and ritterazines: Distinctive dimeric marine-derived steroidal pyrazine alkaloids with intriguing anticancer activities.

Cephalostatins and ritterazines represent fascinating classes of dimeric marine derived steroidal alkaloids with unique chemical structures and promising biological activities. Originally isolated from marine tube worms and the tunicate Ritterella tokioka collected off the coast of Japan, cephalostatins and ritterazines display potent anticancer effects by inducing apoptosis, disrupting cell cycle progression, and targeting multiple molecular pathways. This review covers the chemistry and bioactivities of 45 cephalostatins and ritterazines from 1988 to 2024, highlighting their complex structures and medicinal contributions. With insights into their structure activity relationships (SAR). Key structural elements, such as the pyrazine ring and 5/6 spiroketal moieties, are found crucial for their biological effects, suggesting interactions with lipid membranes or hydrophobic protein domains. Additionally, the formation of oxocarbenium ions from spiroketal cleavage may enhance their potency by covalently modifying DNA. The pharmacokinetics, ADMET and Drug likeness properties of these steroidal alkaloids are thoroughly addressed. Drug likeness analysis shows that these compounds fit well with the Rule of 4 (Ro4) for Protein-Protein Interaction Drugs (PPIDs), underscoring their potential in this area. Ten compounds (20, 27, 33, 34, 39, 40, 41, 42, 43, and 45) have demonstrated favourable pharmacokinetic and ADMET profiles, making them promising candidates for further research. Future efforts should focus on alternative administration routes, structural modifications, and innovative delivery systems, such as prodrugs and nanoparticles, to improve bioavailability and therapeutic effects. Advances in synthetic chemistry, mechanistic insights, and interdisciplinary collaborations will be essential for translating cephalostatins and ritterazines into effective anticancer therapies.

Metformin synergizes with gilteritinib in treating FLT3-mutated leukemia via targeting PLK1 signaling.

Fms-like tyrosine kinase 3 (FLT3) mutations, present in over 30% of acute myeloid leukemia (AML) cases and dominated by FLT3-internal tandem duplication (FLT3-ITD), are associated with poor outcomes in patients with AML. While tyrosine kinase inhibitors (TKIs; e.g., gilteritinib) are effective, they face challenges such as drug resistance, relapse, and high costs. Here, we report that metformin, a cheap, safe, and widely used anti-diabetic agent, exhibits a striking synergistic effect with gilteritinib in treating FLT3-ITD AML. Metformin significantly sensitizes FLT3-ITD AML cells (including TKI-resistant ones) to gilteritinib. Metformin plus gilteritinib (low dose) dramatically suppresses leukemia progression and prolongs survival in FLT3-ITD AML mouse models. Mechanistically, the combinational treatment cooperatively suppresses polo-like kinase 1 (PLK1) expression and phosphorylation of FLT3/STAT5/ERK/mTOR. Clinical analysis also shows improved survival rates in patients with FLT3-ITD AML taking metformin. Thus, the metformin/gilteritinib combination represents a promising and cost-effective treatment for patients with FLT3-mutated AML, particularly for those with low income/affordability.

Combining the novel FLT3 and MERTK dual inhibitor MRX-2843 with venetoclax results in promising antileukemic activity against FLT3-ITD AML.

FMS-like tyrosine kinase 3 (FLT3) mutations occur in approximately one third of acute myeloid leukemia (AML) patients. FLT3-Internal tandem duplication (FLT3-ITD) mutations are the most common FLT3 mutations and are associated with a poor prognosis. Gilteritinib is a FLT3 inhibitor that is US FDA approved for treating adult patients with relapsed/refractory AML and a FLT3 mutation. While gilteritinib monotherapy has improved patient outcome, few patients achieve durable responses. Combining gilteritinib with venetoclax (VEN) appears to make further improvements, though early results suggest that patients with prior exposure to VEN fair much worse than those without prior exposure. MRX-2843 is a promising inhibitor of FLT3 and MERTK. We recently demonstrated that MRX-2843 is equally potent as gilteritinib in FLT3-ITD AML cell lines in vitro and primary patient samples ex vivo. In this study, we investigated the combination of VEN and MRX-2843 against FLT3-ITD AML cells. We found that VEN synergistically enhances cell death induced by MRX-2843 in FLT3-mutated AML cell lines and primary patient samples. Importantly, we found that VEN synergistically enhances cell death induced by MRX-2843 in FLT3-ITD AML cells with acquired resistance to cytarabine (AraC) or VEN+AraC. VEN and MRX-2843 significantly reduce colony-forming capacity of FLT3-ITD primary AML cells. Mechanistic studies show that MRX-2843 decreases Mcl-1 and c-Myc protein levels via transcriptional regulation and combined MRX-2843 and VEN significantly decreases oxidative phosphorylation in FLT3-ITD AML cells. Our findings highlight a promising combination therapy against FLT3-ITD AML, supporting further in vitro and in vivo testing.

Tetramethylpyrazine alleviates ferroptosis and promotes functional recovery in spinal cord injury by regulating GPX4/ACSL4.

OBJECTIVE: Tetramethylpyrazine (TMP) has been demonstrated to alleviate neuronal ferroptosis following spinal cord injury (SCI), thereby promoting neural repair. However, the precise underlying mechanisms remain elusive. METHODS: The SCI model was established using a modified version of Allen's method. TMP (40, 80, 120, and 160 mg/kg) and ras-selective lethal 3 (RSL3) (5 mg/kg) were administered intraperitoneally once daily for 7 days. HE and Nissl staining were employed to examine histomorphology and neurons, respectively. Perls staining was used to identify the distribution of iron. A transmission electron microscope was used to observe the microcosmic morphology of mitochondria. Immunofluorescence staining and Western blot were used to analyze neuronal nuclear protein (NeuN) and glial fibrillary acidic protein (GFAP) surrounding injury sites. Additionally, glutathione peroxidase 4 (GPX4)/NeuN + cells and acyl-CoA synthetase long-chain family member 4 (ACSL4)/NeuN + cells were observed. RT-qPCR was conducted to examine the mRNA expression levels of GPX4 and ACSL4. ELISA were used to quantify the concentrations of GPX4, reactive oxygen species (ROS), L-glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD), and tissue iron. RESULTS: TMP had an inhibitory effect on the concentrations of tissue iron, ROS, GSH, MDA, and SOD. TMP improved the microcosmic morphology of mitochondria and increased GPX4 level while decreasing that of ACSL4. TMP reduced lesion sizes, enhanced neuronal survival, and inhibited glial scar formation. However, the effect of TMP can be effectively reversed by RSL3. CONCLUSION: TMP alleviates neuronal ferroptosis by regulating the GPX4/ACSL4 axis, thereby protecting the remaining neurons surrounding injury sites and reducing glial scar formation.

Dihydropyrazine induces endoplasmic reticulum stress and inhibits autophagy in HepG2 human hepatoma cells.

Dihydropyrazines (DHPs) are formed by non-enzymatic glycation reactions in vivo and in food. We recently reported that 3-hydro-2,2,5,6-tetramethylpyrazine (DHP-3), which is a methyl-substituted DHP, caused severe oxidative stress and cytotoxicity. However, the molecular mechanisms underlying the cytotoxic pathways of the DHP response remain elusive. Because oxidative stress induces endoplasmic reticulum (ER) stress and autophagy, we investigated the ability of DHP-3 to modulate the ER stress and autophagy pathways. DHP-3 activated the ER stress pathway by increasing inositol-requiring enzyme 1 (IRE1) and PKR-like ER kinase (PERK) phosphorylation and transcription factor 6 (ATF6) expression. Moreover, DHP-3 increased the expression of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP), which are downstream targets of PERK. In addition, DHP-3 inhibited the autophagy pathway by increasing the accumulation of microtubule-associated protein 1 light chain 3 alpha-phosphatidylethanolamine conjugate (LC3-II) and p62/sequestosome 1 (p62), while decreasing autophagic flux. Taken together, these results indicate that DHP-3 activates the ER stress pathway and inhibits the autophagy pathway, suggesting that the resulting removal of damaged organelles is inadequate.

Anti-Leukemic Effects of Small Molecule Inhibitor of c-Myc (10058-F4) on Chronic Myeloid Leukemia Cells.

BACKGROUND: As one of the main molecules in BCR-ABL signaling, c-Myc acts as a pivotal key in disease progression and disruption of long-term remission in patients with CML. OBJECTIVES: To clarify the effects of c-Myc inhibition in CML, we examined the anti-tumor property of a well-known small molecule inhibitor of c-Myc 10058-F4 on K562 cell line. METHODS: This experimental study was conducted in K562 cell line for evaluation of cytotoxic activity of 10058-F4 using Trypan blue and MTT assays. Flow cytometry and Quantitative RT-PCR analysis were also conducted to determine its mechanism of action. Additionally, Annexin/PI staining was performed for apoptosis assessment. RESULTS: The results of Trypan blue and MTT assay demonstrated that inhibition of c-Myc, as shown by suppression of c-Myc expression and its associated genes PP2A, CIP2A, and hTERT, could decrease viability and metabolic activity of K562 cells, respectively. Moreover, a robust elevation in cell population in G1-phase coupled with up-regulation of p21 and p27 expression shows that 10058-F4 could hamper cell proliferation, at least partly, through induction of G1 arrest. Accordingly, we found that 10058-F4 induced apoptosis via increasing Bax and Bad; In contrast, no significant alterations were observed NF-KB pathway-targeted anti-apoptotic genes in the mRNA levels. Notably, disruption of the NF-κB pathway with bortezomib as a common proteasome inhibitor sensitized K562 cells to the cytotoxic effect of 10058-F4, substantiating the fact that the NF-κB axis functions probably attenuate the K562 cells sensitivity to c-Myc inhibition. CONCLUSIONS: It can be concluded from the results of this study that inhibition of c-Myc induces anti-neoplastic effects on CML-derived K562 cells as well as increases the efficacy of imatinib. For further insight into the safety and effectiveness of 10058-F4 in CML, in vivo studies will be required.