Mnk kinase pathway: Cellular functions and biological outcomes

Development of an Imidazopyridazine-Based MNK1/2 Inhibitor for the Treatment of Lymphoma

The mitogen-activated protein kinase-interacting protein kinases (MNKs) are the only kinases known to phosphorylate eukaryotic translation initiation factor 4E (eIF4E) at Ser209, which plays a significant role in cap-dependent translation. Dysregulation of the MNK/eIF4E axis has been found in various solid tumors and hematological malignancies, including diffuse large B-cell lymphoma (DLBCL). Herein, structure-activity relationship studies and docking models determined that 20j exhibits excellent MNK1/2 inhibitory activity, stability, and hERG safety. 20j exhibits strong and broad antiproliferative activity against different cancer cell lines, especially GCB-DLBCL DOHH2. 20j suppresses the phosphorylation of eIF4E in Hela cells (IC50 = 90.5 nM) and downregulates the phosphorylation of eIF4E and 4E-BP1 in A549 cells. In vivo studies first revealed that ibrutinib enhances the antitumor effect of 20j without side effects in a DOHH2 xenograft model. This study provided a solid foundation for the future development of a MNK inhibitor for GCB-DLBCL treatment.

Mechanisms of Sepsis-Induced Acute Lung Injury and Advancements of Natural Small Molecules in Its Treatment

Sepsis-induced acute lung injury (ALI), characterized by widespread lung dysfunction, is associated with significant morbidity and mortality due to the lack of effective pharmacological treatments available clinically. Small-molecule compounds derived from natural products represent an innovative source and have demonstrated therapeutic potential against sepsis-induced ALI. These natural small molecules may provide a promising alternative treatment option for sepsis-induced ALI. This review aims to summarize the pathogenesis of sepsis and potential therapeutic targets. It assembles critical updates (from 2014 to 2024) on natural small molecules with therapeutic potential against sepsis-induced ALI, detailing their sources, structures, effects, and mechanisms of action.

Vinorelbine causes a neuropathic pain-like state in mice via STING and MNK1 signaling associated with type I interferon induction

Type I interferons (IFNs) increase the excitability of dorsal root ganglia (DRGs) neurons via MNK-eIF4E signaling to promote pain sensitization in mice. Activation of stimulator of interferon response cGAMP interactor 1 (STING) signaling is pivotal for type I IFN induction. We hypothesized that vinorelbine, a chemotherapeutic and activator of STING, would cause a neuropathic pain-like state in mice via STING signaling in DRG neurons associated with IFN production. Vinorelbine caused tactile allodynia and grimacing in wild-type (WT) mice and increased p-IRF3, type I IFNs, and p-eIF4E in peripheral nerves. Supporting our hypothesis, vinorelbine failed to induce IRF3-IFNs-MNK-eIF4E in StingGt/Gt mice and, subsequently, failed to cause pain. The vinorelbine-elicited increase of p-eIF4E was not observed in Mknk1-/- (MNK1 knockout) mice in peripheral nerves consistent with the attenuated pro-nociceptive effect of vinorelbine in these mice. Our findings show that activation of STING signaling in the periphery causes a neuropathic pain-like state through type I IFN signaling to DRG nociceptors.

A tRF-5a fragment that regulates radiation resistance of colorectal cancer cells by targeting MKNK1

Radiotherapy serves as a crucial strategy in the treatment of colorectal cancer (CRC). However, its efficacy is often hindered by the challenge of radiation resistance. Although the literature suggests that some tRNA-derived small RNAs (tsRNAs) are associated with various cancers, studies reporting the relationship of tsRNAs with cancer cell radiosensitivity have not been published yet. In our study, we utilized tsRNAs sequencing to predict differentially expressed tsRNAs in two CRC cells and their radioresistant cells, and 10 tsRNAs with significant differences in expression were validated by qPCR. The target genes of tRF-16-7X9PN5D were predicted and verified by the bioinformatics, dual-luciferase reporter gene assay and western blotting analyses. Wound healing, colony formation, transwell invasion and CCK-8 assays were performed to detect the effects of tRF-16-7X9PN5D on cell function and radiosensitivity. Western blotting evaluated the relationship between tRF-16-7X9PN5D and the MKNK-eIF4E axis. Our findings demonstrated that tRF-16-7X9PN5D expression was substantially downregulated in radioresistant CRC cells. Furthermore, tRF-16-7X9PN5D could promote CRC cells' ability to proliferate, migrate, invade and obtain radiation resistance by targeting MKNK1. Finally, tRF-16-7X9PN5D could regulate eIF4E phosphorylation via MKNK1. This investigation indicated that tRF-16-7X9PN5D has an essential regulatory role in the radiation resistance of CRC by directly targeting MKNK1, and may be a new pathway for regulating the CRC radiosensitivity.

MNK, mTOR or eIF4E-selecting the best anti-tumor target for blocking translation initiation

Overexpression of eIF4E is common in patients with various solid tumors and hematologic cancers. As a potential anti-cancer target, eIF4E has attracted extensive attention from researchers. At the same time, mTOR kinases inhibitors and MNK kinases inhibitors, which are directly related to regulation of eIF4E, have been rapidly developed. To explore the optimal anti-cancer targets among MNK, mTOR, and eIF4E, this review provides a detailed classification and description of the anti-cancer activities of promising compounds. In addition, the structures and activities of some dual-target inhibitors are briefly described. By analyzing the different characteristics of the inhibitors, it can be concluded that MNK1/2 and eIF4E/eIF4G interaction inhibitors are superior to mTOR inhibitors. Simultaneous inhibition of MNK and eIF4E/eIF4G interaction may be the most promising anti-cancer method for targeting translation initiation.

Molecular targeting of the UDP-glucuronosyltransferase enzymes in high-eukaryotic translation initiation factor 4E refractory/relapsed acute myeloid leukemia patients: a randomized phase II trial of vismodegib, ribavirin with or without decitabine

Drug resistance underpins poor outcomes in many malignancies including refractory and relapsed acute myeloid leukemia (R/R AML). Glucuronidation is a common mechanism of drug inactivation impacting many AML therapies, e.g., cytarabine, decitabine, azacytidine and venetoclax. In AML cells, the capacity for glucuronidation arises from increased production of the UDP-glucuronosyltransferase 1A (UGT1A) enzymes. UGT1A elevation was first observed in AML patients who relapsed after response to ribavirin, a drug used to target the eukaryotic translation initiation factor eIF4E, and subsequently in patients who relapsed on cytarabine. UGT1A elevation resulted from increased expression of the sonic-hedgehog transcription factor GLI1. Vismodegib inhibited GLI1, decreased UGT1A levels, reduced glucuronidation of ribavirin and cytarabine, and re-sensitized cells to these drugs. Here, we examined if UGT1A protein levels, and thus glucuronidation activity, were targetable in humans and if this corresponded to clinical response. We conducted a phase II trial using vismodegib with ribavirin, with or without decitabine, in largely heavily pre-treated patients with high-eIF4E AML. Pre-therapy molecular assessment of patients' blasts indicated highly elevated UGT1A levels relative to healthy volunteers. Among patients with partial response, blast response or prolonged stable disease, vismodegib reduced UGT1A levels, which corresponded to effective targeting of eIF4E by ribavirin. In all, our studies are the first to demonstrate that UGT1A protein, and thus glucuronidation, are targetable in humans. These studies pave the way for the development of therapies that impair glucuronidation, one of the most common drug deactivation modalities. Clinicaltrials.gov: NCT02073838.

From signalling pathways to targeted therapies: unravelling glioblastoma's secrets and harnessing two decades of progress

Glioblastoma, a rare, and highly lethal form of brain cancer, poses significant challenges in terms of therapeutic resistance, and poor survival rates for both adult and paediatric patients alike. Despite advancements in brain cancer research driven by a technological revolution, translating our understanding of glioblastoma pathogenesis into improved clinical outcomes remains a critical unmet need. This review emphasises the intricate role of receptor tyrosine kinase signalling pathways, epigenetic mechanisms, and metabolic functions in glioblastoma tumourigenesis and therapeutic resistance. We also discuss the extensive efforts over the past two decades that have explored targeted therapies against these pathways. Emerging therapeutic approaches, such as antibody-toxin conjugates or CAR T cell therapies, offer potential by specifically targeting proteins on the glioblastoma cell surface. Combination strategies incorporating protein-targeted therapy and immune-based therapies demonstrate great promise for future clinical research. Moreover, gaining insights into the role of cell-of-origin in glioblastoma treatment response holds the potential to advance precision medicine approaches. Addressing these challenges is crucial to improving outcomes for glioblastoma patients and moving towards more effective precision therapies.

Role of irisin in bone diseases

Bone diseases are common among middle-aged and elderly people, and harm to activities of daily living (ADL) and quality of life (QOL) for patients. It is crucial to search for key regulatory factors associated with the development of bone diseases and explore potential therapeutic targets for bone diseases. Irisin is a novel myokine that has been discovered in recent years. Accumulating evidence indicates that irisin has beneficial effects in the treatment of various diseases such as metabolic, cardiovascular and neurological disorders, especially bone-related diseases. Recent studies had shown that irisin plays the role in various bone diseases such as osteoarthritis, osteoporosis and other bone diseases, suggesting that irisin may be a potential molecule for the prevention and treatment of bone diseases. Therefore, in this review, by consulting the related domestic and international literature of irisin and bone diseases, we summarized the specific regulatory mechanisms of irisin in various bone diseases, and provided a systematic theoretical basis for its application in the diagnosis and treatment of the bone diseases.

Canagliflozin shares common mTOR and MAPK signaling mechanisms with other lifespan extension treatments

Long-lived mouse models and treatments that extend lifespan, such as Rapamycin, acarbose and 17α- -estradiol, lead to reduction in mTORC1 activity, declines in cap-dependent translation and increases in cap-independent translation. In addition, these treatments reduce the MEK-ERK-MNK (ERK1-2) signaling cascade, leading to reduction in eIF4E phosphorylation, which also regulates mRNA translation. Here, we report that Canagliflozin, a drug that extends lifespan only in male mice reduces mTORC1 and ERK1-2 signaling in male mice only. The data suggest reduction in mTORC1 and ERK pathways are common mechanisms shared by both genetic and pharmacological models of slowed aging in mice. Our data also reveal a significant sexual dimorphism in the ERK1-2 signaling pathway which might help to explain why some drugs can extend lifespan in males but have no effects in female mice.

Aging Rate Indicators: Speedometers for Aging Research in Mice

A "biomarker of aging" is conceptualized as an index of how far an individual has moved along the path from youth to old age. In contrast, an aging rate indicator (ARI) represents a measure of speed, rather than distance, that is, a measure of how rapidly the individual is moving toward the phenotypic changes typical of old age. This essay presents and reviews recent data suggesting common characteristics of slow-aging mice, whether the slowed aging is caused by a mutant allele, the calorie restriction diet, or drugs that slow aging and extend mean and maximal lifespan. Some of the candidate ARIs, shared by nine varieties of slow-aging mice, are physiological changes seen in fat, fat-associated macrophages, muscle, liver, brain, and plasma. Others are molecular measurements, reflecting activity of mTORC1, selective mRNA translation, or each of six MAP kinases in two distinct MAPK cascades in liver, muscle, or kidney. Changes in ARIs are notable in young adult mice after 8 months of drug or diet exposure, are detectable in mutant mice at least as early as 4-6 months of age, and persist until at least 18-22 months. Many of the candidate ARIs are thought to play an influential role in cognition, inflammation, exercise responses, and control of metabolic rate, and are thus plausible as modulators of age-related physiological and neurological illnesses. In principle, screening for drugs that induce alterations in ARIs in normal young adult mice might facilitate the search for preventive medicines that can retard aging and late-life illnesses in mice or in human populations.

Medicinal chemistry approaches to target the MNK-eIF4E axis in cancer

Aberrant translation of proteins that promote cell proliferation is an essential factor that defines oncogenic processes and cancer. The process for ribosomal translation of proteins from mRNA requires an essential initiation step which is controlled by the protein eIF4E, which binds the RNA 5'-cap and forms the eIF4F complex that subsequently translates protein. Typically, eIF4E is activated by phosphorylation on Ser209 by MNK1 and MNK2 kinases. Substantial work has shown that eIF4E and MNK1/2 are dysregulated in many cancers and this axis has therefore become an active area of interest for developing new cancer therapeutics. This review summarizes and discusses recent work to develop small molecules that target different steps in the MNK-eIF4E axis as potential cancer therapeutics. The aim of this review is to cover the breadth of different molecular approaches being taken and the medicinal chemistry basis for their optimization and testing as new cancer therapeutics.

Vinorelbine causes a neuropathic pain-like state in mice via STING and MNK1 signaling associated with type I interferon induction

Type I interferons (IFNs) increase the excitability of dorsal root ganglion (DRG) neurons via activation of MNK-eIF4E translation signaling to promote pain sensitization in mice. Activation of STING signaling is a key component of type I IFN induction. Manipulation of STING signaling is an active area of investigation in cancer and other therapeutic areas. Vinorelbine is a chemotherapeutic that activates STING and has been shown to cause pain and neuropathy in oncology clinical trials in patients. There are conflicting reports on whether STING signaling promotes or inhibits pain in mice. We hypothesized that vinorelbine would cause a neuropathic pain-like state in mice via STING and signaling pathways in DRG neurons associated with type I IFN induction. Vinorelbine (10 mg/kg, i.v.) induced tactile allodynia and grimacing in WT male and female mice and increased p-IRF3 and type I IFN protein in peripheral nerves. In support of our hypothesis, vinorelbine-mediated pain was absent in male and female StingGt/Gt mice. Vinorelbine also failed to induce IRF3 and type I IFN signaling in these mice. Since type I IFNs engage translational control via MNK1-eIF4E in DRG nociceptors, we assessed vinorelbine-mediated p-eIF4E changes. Vinorelbine increased p-eIF4E in DRG in WT animals but not in StingGt/Gt or Mknk1-/- (MNK1 KO) mice. Consistent with these biochemical findings, vinorelbine had an attenuated pro-nociceptive effect in male and female MNK1 KO mice. Our findings support the conclusion that activation of STING signaling in the peripheral nervous system causes a neuropathic pain-like state that is mediated by type I IFN signaling to DRG nociceptors.

eIF4E phosphorylation recruits β-catenin to mRNA cap and promotes Wnt pathway translation in dentate gyrus LTP maintenance

The mRNA cap-binding protein, eukaryotic initiation factor 4E (eIF4E), is crucial for translation and regulated by Ser209 phosphorylation. However, the biochemical and physiological role of eIF4E phosphorylation in translational control of long-term synaptic plasticity is unknown. We demonstrate that phospho-ablated Eif4e^S209A Knockin mice are profoundly impaired in dentate gyrus LTP maintenance in vivo, whereas basal perforant path-evoked transmission and LTP induction are intact. mRNA cap-pulldown assays show that phosphorylation is required for synaptic activity-induced removal of translational repressors from eIF4E, allowing initiation complex formation. Using ribosome profiling, we identified selective, phospho-eIF4E-dependent translation of the Wnt signaling pathway in LTP. Surprisingly, the canonical Wnt effector, β-catenin, was massively recruited to the eIF4E cap complex following LTP induction in wild-type, but not Eif4e^S209A, mice. These results demonstrate a critical role for activity-evoked eIF4E phosphorylation in dentate gyrus LTP maintenance, remodeling of the mRNA cap-binding complex, and specific translation of the Wnt pathway.

Mnk1/2 kinases regulate memory and autism-related behaviours via Syngap1

MAPK interacting protein kinases 1 and 2 (Mnk1/2) regulate a plethora of functions, presumably via phosphorylation of their best characterized substrate, eukaryotic translation initiation factor 4E (eIF4E) on Ser209. Here, we show that, whereas deletion of Mnk1/2 (Mnk double knockout) impairs synaptic plasticity and memory in mice, ablation of phospho-eIF4E (Ser209) does not affect these processes, suggesting that Mnk1/2 possess additional downstream effectors in the brain. Translational profiling revealed only a small overlap between the Mnk1/2- and phospho-eIF4E(Ser209)-regulated translatome. We identified the synaptic Ras GTPase activating protein 1 (Syngap1), encoded by a syndromic autism gene, as a downstream target of Mnk1 because Syngap1 immunoprecipitated with Mnk1 and showed reduced phosphorylation (S788) in Mnk double knockout mice. Knockdown of Syngap1 reversed memory deficits in Mnk double knockout mice and pharmacological inhibition of Mnks rescued autism-related phenotypes in Syngap1+/- mice. Thus, Syngap1 is a downstream effector of Mnk1, and the Mnks-Syngap1 axis regulates memory formation and autism-related behaviours.

MNK1 and MNK2 Expression in the Human Dorsal Root and Trigeminal Ganglion

Mitogen activated protein kinase interacting kinases (MNK) 1 and 2 are serine/threonine protein kinases that play an important role in translation of mRNAs through their phosphorylation of the RNA 5'-cap binding protein, eukaryotic translation initiation factor (eIF) 4E. These kinases are downstream targets for mitogen activated protein kinases (MAPKs), extracellular activity regulated protein kinase (ERK) and p38. MNKs have been implicated in the sensitization of peripheral nociceptors of the dorsal root and trigeminal ganglion (DRG and TG) using transgenic mouse lines and through the use of specific inhibitors of MNK1 and MNK2. While specific knockout of the Mknk1 gene suggests that it is the key isoform for regulation of nociceptor excitability and nociceptive behaviors in mice, both MKNK1 and MKNK2 genes are expressed in the DRG and TG of mice and humans based on RNA sequencing experiments. Single cell sequencing in mice suggests that Mknk1 and Mknk2 may be expressed in different populations of nociceptors. We sought to characterize mRNA expression in human DRG and TG (N = 3 ganglia for both DRG and TG) for both MNK1 and MNK2. Our results show that both genes are expressed by nearly all neurons in both human ganglia with expression in other cell types as well. Our findings provide evidence that MNK1 and MNK2 are expressed by human nociceptors of males and females and suggest that efforts to pharmacologically target MNKs for pain would likely be translatable due its conserved expression in both species.

Computational and Functional Analysis of Structural Features in the ZAKα Kinase

The kinase ZAKα acts as the proximal sensor of translational impairment and ribotoxic stress, which results in the activation of the MAP kinases p38 and JNK. Despite recent insights into the functions and binding partners of individual protein domains in ZAKα, the mechanisms by which ZAKα binds ribosomes and becomes activated have remained elusive. Here, we highlight a short, thrice-repeated, and positively charged peptide motif as critical for the ribotoxic stress-sensing function of the Sensor (S) domain of ZAKα. We use this insight to demonstrate that the mutation of the SAM domain uncouples ZAKα activity from ribosome binding. Finally, we use 3D structural comparison to identify and functionally characterize an additional folded domain in ZAKα with structural homology to YEATS domains. These insights allow us to formulate a model for ribosome-templated ZAKα activation based on the re-organization of interactions between modular protein domains. In sum, our work both advances our understanding of the protein domains and 3D architecture of the ZAKα kinase and furthers our understanding of how the ribotoxic stress response is activated.

Regulation of germline proteostasis by HSF1 and insulin/IGF-1 signaling

Protein homeostasis (proteostasis) is essential for cellular function and organismal health and requires the concerted actions of protein synthesis, folding, transport, and turnover. In sexually reproducing organisms, the immortal germline lineage passes genetic information across generations. Accumulating evidence indicates the importance of proteome integrity for germ cells as genome stability. As gametogenesis involves very active protein synthesis and is highly energy-demanding, it has unique requirements for proteostasis regulation and is sensitive to stress and nutrient availability. The heat shock factor 1 (HSF1), a key transcriptional regulator of cellular response to cytosolic and nuclear protein misfolding has evolutionarily conserved roles in germline development. Similarly, insulin/insulin-like growth factor-1 (IGF-1) signaling, a major nutrient-sensing pathway, impacts many aspects of gametogenesis. Here, we focus on HSF1 and IIS to review insights into their roles in germline proteostasis and discuss the implications on gamete quality control during stress and aging.

Proteome diversification by mRNA translation in cancer

mRNA translation is a highly conserved and tightly controlled mechanism for protein synthesis and is well known to be altered by oncogenes to promote cancer development. This distorted mRNA translation is accompanied by the vulnerability of cancer to inhibitors of key mRNA translation components. Novel studies also suggest that these alternations could be utilized for immunotherapy. Ribosome heterogeneity and alternative responses to nutrient shortages, which aid cancer growth and spread, are proposed to elicit aberrant protein production but may also result in previously unidentified therapeutic targets, such as the presentation of cancer-specific peptides at the surface of cancer cells (neoepitopes). This review will assess the driving forces in tRNA and ribosome function that underlie proteome diversification due to alterations in mRNA translation in cancer cells.

Finnish-specific AKT2 gene variant leads to impaired insulin signalling in myotubes

Finnish-specific gene variant p.P50T/AKT2 (minor allele frequency (MAF) = 1.1%) is associated with insulin resistance and increased predisposition to type 2 diabetes. Here, we have investigated in vitro the impact of the gene variant on glucose metabolism and intracellular signalling in human primary skeletal muscle cells, which were established from 14 male p.P50T/AKT2 variant carriers and 14 controls. Insulin-stimulated glucose uptake and glucose incorporation into glycogen were detected with 2-[1,2-3H]-deoxy-D-glucose and D-[14C]-glucose, respectively, and the rate of glycolysis was measured with a Seahorse XFe96 analyzer. Insulin signalling was investigated with Western blotting. The binding of variant and control AKT2-PH domains to phosphatidylinositol (3,4,5)-trisphosphate (PI(3,4,5)P3) was assayed using PIP StripsTM Membranes. Protein tyrosine kinase and serine-threonine kinase assays were performed using the PamGene® kinome profiling system. Insulin-stimulated glucose uptake and glycogen synthesis in myotubes in vitro were not significantly affected by the genotype. However, the insulin-stimulated glycolytic rate was impaired in variant myotubes. Western blot analysis showed that insulin-stimulated phosphorylation of AKT-Thr308, AS160-Thr642 and GSK3β-Ser9 was reduced in variant myotubes compared to controls. The binding of variant AKT2-PH domain to PI(3,4,5)P3 was reduced as compared to the control protein. PamGene® kinome profiling revealed multiple differentially phosphorylated kinase substrates, e.g. calmodulin, between the genotypes. Further in silico upstream kinase analysis predicted a large-scale impairment in activities of kinases participating, for example, in intracellular signal transduction, protein translation and cell cycle events. In conclusion, myotubes from p.P50T/AKT2 variant carriers show multiple signalling alterations which may contribute to predisposition to insulin resistance and T2D in the carriers of this signalling variant.

MNK1 and MNK2 expression in the human dorsal root and trigeminal ganglion

Mitogen activated protein kinase interacting kinases (MNK) 1 and 2 are serine/threonine protein kinases that play an important role in translation of mRNAs through their phosphorylation of the RNA 5’-cap binding protein, eukaryotic translation initiation factor (eIF) 4E. These kinases are downstream targets for mitogen activated protein kinases (MAPKs), extracellular activity regulated protein kinase (ERK) and p38. MNKs have been implicated in the sensitization of peripheral nociceptors of the dorsal root and trigeminal ganglion (DRG and TG) using transgenic mouse lines and through the use of specific inhibitors of MNK1 and MNK2. While specific knockout of the Mknk1 gene suggests that it is the key isoform for regulation of nociceptor excitability and nociceptive behaviors in mice, both MKNK1 and MKNK2 genes are expressed in the DRG and TG of mice and humans based on RNA sequencing experiments. Single cell sequencing in mice suggests that Mknk1 and Mknk2 may be expressed in different populations of nociceptors. We sought to characterize mRNA expression in human DRG and TG for both MNK1 and MNK2. Our results show that both genes are expressed by nearly all neurons in both human ganglia with expression in other cell types as well. Our findings provide evidence that MNK1 and MNK2 are expressed by human nociceptors and suggest that efforts to pharmacologically target MNKs for pain would likely be translatable due its conserved expression in both species.

MNK Proteins as Therapeutic Targets in Leukemia

In leukemia, resistance to therapy is a major concern for survival. MAPK-interacting kinases (MNKs) have been identified as important activators of oncogenic-related signaling and may be mediators of resistance. Recent studies in leukemia models, especially acute myeloid leukemia (AML), have focused on targeting MNKs together with other inhibitors or treating chemotherapy-resistant cells with MNK inhibitors. The preclinical demonstrations of the efficacy of MNK inhibitors in these combination formats would suggest a promising potential for use in clinical trials. Optimizing MNK inhibitors and testing in leukemia models is actively being pursued and may have important implications for the future. These studies are furthering the understanding of the mechanisms of MNKs in cancer which could translate to clinical studies.

Immune-related pulmonary toxicities of checkpoint inhibitors in non-small cell lung cancer: Diagnosis, mechanism, and treatment strategies

Immune checkpoint inhibitors (ICI) therapy based on programmed cell death-1 (PD-1) and programmed cell death ligand 1 (PD-L1) has changed the treatment paradigm of advanced non-small cell lung cancer (NSCLC) and improved the survival expectancy of patients. However, it also leads to immune-related adverse events (iRAEs), which result in multiple organ damage. Among them, the most common one with the highest mortality in NSCLC patients treated with ICI is checkpoint inhibitor pneumonitis (CIP). The respiratory signs of CIP are highly coincident and overlap with those in primary lung cancer, which causes difficulties in detecting, diagnosing, managing, and treating. In clinical management, patients with serious CIP should receive immunosuppressive treatment and even discontinue immunotherapy, which impairs the clinical benefits of ICIs and potentially results in tumor recrudesce. Therefore, accurate diagnosis, detailedly dissecting the pathogenesis, and developing reasonable treatment strategies for CIP are essential to prolong patient survival and expand the application of ICI. Herein, we first summarized the diagnosis strategies of CIP in NSCLC, including the classical radiology examination and the rising serological test, pathology test, and artificial intelligence aids. Then, we dissected the potential pathogenic mechanisms of CIP, including disordered T cell subsets, the increase of autoantibodies, cross-antigens reactivity, and the potential role of other immune cells. Moreover, we explored therapeutic approaches beyond first-line steroid therapy and future direction based on targeted signaling pathways. Finally, we discussed the current impediments, future trends, and challenges in fighting ICI-related pneumonitis.

13-Acetoxysarcocrassolide induces apoptosis in human hepatocellular carcinoma cells through mitochondrial dysfunction and suppression of the PI3K/AKT/mTOR/p70S6K signalling pathway

CONTEXT

13-Acetoxysarcocrasside, isolated from the Taiwanese soft coral Sarcophyton crassocaule Moser (Alcyoniidae), has biological activity and induces apoptosis in hepatocellular carcinoma cells.

OBJECTIVE

To elucidate the mechanisms underlying apoptosis induced by 13-acetoxysarcocrasside in HA22T and HepG2 hepatocellular carcinoma cells.

MATERIAL AND METHODS

MTT and morphology assays were employed to assess the anti-proliferative effects of 13-acetoxysarcocrasside (1-5 μM). TUNEL/DAPI staining and annexin V-fluorescein isothiocyanate/propidium iodide staining were used to detect apoptosis. Cells were treated with13-acetoxysarcocrassolide (0, 1, 2, and 4 μM) for 24 h, and the mechanism of cells apoptotic was detected by western blotting. Cells treated with DMSO were the control.

RESULTS

Survival of the cells decreased with the addition of 13-acetoxysarcocrassolide, and at 4 μM cell survival was inhibited by approximately 40%. After treatment of cells with 13-acetoxysarcocrassolide, the incidence of early/late apoptosis to be 0.3%/0.5%∼5.4%/22.7% for HA22T cells, in the HePG2 cells were 0.6%/0.2%∼14.4%/23.7%. Western blotting analysis showed that the expression of Bax, Bad, cleaved caspase 3, cleaved caspase 9, cleaved-PARP-1, cytochrome c, and p-4EBP1 increased with an increasing concentration of 13-acetoxysarcocrasside (0, 1, 2, and 4 μM), whereas that of Bcl-2, Bcl-xL, Mcl-1, p-Bad, p-PI3K, p-AKT, p-mTOR, p-70S6K, p-S6, p-eIF4E, and p-eIF4B decreased.

DISCUSSION AND CONCLUSIONS

Apoptosis induced by 13-acetoxysarcocrassolide in HA22T and HepG2 cells is mediated by mitochondrial dysfunction and inactivation of the PI3K/AKT/mTOR/p70S6K pathway. The potential of 13-acetoxysarcocrassolide as a chemotherapeutic agent should be further assessed for use in human hepatocellular carcinoma treatment.

The role of immune checkpoints in cardiovascular disease

Immune checkpoint inhibitors (ICI) are monoclonal antibodies which bind to immune checkpoints (IC) and their ligands to prevent inhibition of T-cell activation by tumor cells. Currently, multiple ICI are approved targeting Cytotoxic T-lymphocyte antigen 4 (CTLA-4), Programmed Death Protein 1 (PD-1) and its ligand PD-L1, and Lymphocyte-activation gene 3 (LAG-3). This therapy has provided potent anti-tumor effects and improved prognosis for many cancer patients. However, due to systemic effects, patients can develop immune related adverse events (irAE), including possible life threatening cardiovascular irAE, like atherosclerosis, myocarditis and cardiomyopathy. Inhibition of vascular IC is associated with increased atherosclerotic burden and plaque instability. IC protect against atherosclerosis by inhibiting T-cell activity and cytokine production, promoting regulatory T-cell differentiation and inducing T-cell exhaustion. In addition, PD-L1 on endothelial cells might promote plaque stability by reducing apoptosis and increasing expression of tight junction molecules. In the heart, IC downregulate the immune response to protect against cardiac injury by reducing T-cell activity and migration. Here, inhibition of IC could induce life-threatening T-cell-mediated-myocarditis. One proposed purpose behind lymphocyte infiltration is reaction to cardiac antigens, caused by decreased self-tolerance, and thereby increased autoimmunity because of IC inhibition. In addition, there are several reports of ICI-mediated cardiomyopathy with immunoglobulin G expression on cardiomyocytes, indicating an autoimmune response. IC are mostly known due to their cardiotoxicity. However, t his review compiles current knowledge on mechanisms behind IC function in cardiovascular disease with the aim of providing an overview of possible therapeutic targets in prevention or treatment of cardiovascular irAEs.

Design, Synthesis and Evaluation of Novel Phorbazole C Derivatives as MNK Inhibitors through Virtual High-Throughput Screening

MNKs (mitogen-activated protein kinase-interacting protein kinases) phosphorylate eIF4E at Ser209 to control the translation of certain mRNAs and regulate the process of cell proliferation, cell migration and invasion, etc. Development of MNK inhibitors would be an effective treatment for related diseases. We used the MarineChem3D database to identify hit compounds targeting the protein MNK1 and MNK2 through high-throughput screening. Compounds from the phorbazole family showed good interactions with MNK1, and phorbazole C was selected as our hit compound. By analyzing the binding mode, we designed and synthesized 29 derivatives and evaluated their activity against MNKs, of which, six compounds showed good inhibition to MNKs. We also confirmed three interactions between this kind of compound and MNK1, which are vital for the activity. In conclusion, we report series of novel MNK inhibitors inspired from marine natural products and their relative structure–activity relationship. This will provide important information for further developing MNK inhibitors based on this kind of structure.

Towards Kinase Inhibitor Therapies for Fragile X Syndrome: Tweaking Twists in the Autism Spectrum Kinase Signaling Network

Absence of the Fragile X Mental Retardation Protein (FMRP) causes autism spectrum disorders and intellectual disability, commonly referred to as the Fragile X syndrome. FMRP is a negative regulator of protein translation and is essential for neuronal development and synapse formation. FMRP is a target for several post-translational modifications (PTMs) such as phosphorylation and methylation, which tightly regulate its cellular functions. Studies have indicated the involvement of FMRP in a multitude of cellular pathways, and an absence of FMRP was shown to affect several neurotransmitter receptors, for example, the GABA receptor and intracellular signaling molecules such as Akt, ERK, mTOR, and GSK3. Interestingly, many of these molecules function as protein kinases or phosphatases and thus are potentially amendable by pharmacological treatment. Several treatments acting on these kinase-phosphatase systems have been shown to be successful in preclinical models; however, they have failed to convincingly show any improvements in clinical trials. In this review, we highlight the different protein kinase and phosphatase studies that have been performed in the Fragile X syndrome. In our opinion, some of the paradoxical study conclusions are potentially due to the lack of insight into integrative kinase signaling networks in the disease. Quantitative proteome analyses have been performed in several models for the FXS to determine global molecular processes in FXS. However, only one phosphoproteomics study has been carried out in Fmr1 knock-out mouse embryonic fibroblasts, and it showed dysfunctional protein kinase and phosphatase signaling hubs in the brain. This suggests that the further use of phosphoproteomics approaches in Fragile X syndrome holds promise for identifying novel targets for kinase inhibitor therapies.

The Candida albicans toxin candidalysin mediates distinct epithelial inflammatory responses through p38 and EGFR-ERK pathways

The fungal pathogen Candida albicans secretes the peptide toxin candidalysin, which damages epithelial cells and drives an innate inflammatory response mediated by the epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase (MAPK) pathways and the transcription factor c-Fos. In cultured oral epithelial cells (OECs), candidalysin activated the p38 MAPK signaling pathway, which resulted in heat shock protein 27 (Hsp27) activation, IL-6 release, and EGFR phosphorylation without influencing the induction of c-Fos. p38 activation was not triggered by EGFR but by two non-redundant pathways involving MAPK kinases (MKKs) and the kinase Src, which differentially controlled p38 signaling outputs. Whereas MKKs mainly promoted p38-dependent release of IL-6, Src promoted p38-mediated phosphorylation of EGFR in a ligand-independent fashion. In parallel, candidalysin also activated the EGFR-ERK pathway in a manner that depended on EGFR ligands, resulting in c-Fos activation and release of the neutrophil-activating chemokines G-CSF and GM-CSF. In mice, p38 was important for the early clearance events of oral C. albicans infection, but c-Fos was not. These findings delineate how candidalysin activates the p38 and ERK MAPK pathways that differentially contribute to immune activation during C. albicans infection.

Inhibiting MNK kinases promotes macrophage immunosuppressive phenotype to limit CD8+ T cell anti-tumor immunity

To elicit effective anti-tumor responses, CD8+ T cells need to infiltrate tumors and sustain their effector function within the immunosuppressive tumor microenvironment. Here we evaluate the role of MNK kinase activity in regulating CD8+ T cell infiltration and anti-tumor activity in pancreatic and thyroid tumors. We first show that human pancreatic and thyroid tumors with increased MNK kinase activity are associated with decreased infiltration by CD8+ T cells. We then show that while MNK inhibitors increase CD8+ T cells in these tumors, they induce a T cell exhaustion phenotype in the tumor microenvironment. Mechanistically, we show that the exhaustion phenotype is not caused by upregulation of PD-L1 but by tumor-associated macrophages (TAMs) becoming more immunosuppressive following MNK inhibitor treatment. Reversal of CD8+ T cell exhaustion by an anti-PD-1 antibody or TAM depletion synergizes with MNK inhibitors to control tumor growth and prolong animal survival. Importantly, we show in ex vivo human pancreatic tumor slice cultures that MNK inhibitors increase the expression of markers associated with immunosuppressive TAMs. Together, these findings demonstrate a previously unknown role of MNK kinases in modulating a pro-tumoral phenotype in macrophages and identify combination regimens involving MNK inhibitors to enhance anti-tumor immune responses.

The Sphingolipid Inhibitors Ceranib-2 and SKI-II Reduce Measles Virus Replication in Primary Human Lymphocytes: Effects on mTORC1 Downstream Signaling

The bioactive sphingolipids ceramide and sphingosine-1-phosphate (S1P) are involved in the regulation of cell homeostasis and activity ranging from apoptosis to proliferation. We recently described that the two compounds ceranib-2 (inhibiting acid ceramidase) and SKI-II [inhibiting the sphingosine kinases 1 and − 2 (SphK1/2)] reduce mTORC1 activity and measles virus (MV) replication in human primary peripheral blood lymphocytes (PBL) by about one log step. We now further investigated whether mTORC1 downstream signaling and viral protein expression may be affected by ceranib-2 and/or SKI-II. Western blot analyses showed that in uninfected cells the phosphorylation of the eukaryotic initiation factor 4E (eIF4E) was reduced by both inhibitors. Interestingly, MV infection led to an increase of rpS6 protein levels and phosphorylation of eIF4E. Treatment with both inhibitors reduced the rpS6 protein expression, and in addition, SKI-II reduced rpS6 phosphorylation. The phosphorylation of eIF4E was slightly reduced by both inhibitors. In addition, SKI-II led to reduced levels of IKK in MV-infected cells. Both inhibitors reduced the expression of viral proteins and the titers of newly synthesized MV by approximately one log step. As expected, SKI-II and rapamycin reduced also the virally encoded GFP expression; however, ceranib-2 astonishingly led to increased levels of GFP fluorescence. Our findings suggest that the inhibitors ceranib-2 and SKI-II act via differential mechanisms on MV replication. The observed effects on mTORC1 downstream signaling, predominantly the reduction of rpS6 levels by both inhibitors, may affect the translational capacity of the cells and contribute to the antiviral effect in human primary PBL.

Specific mesoderm subset derived from human pluripotent stem cells ameliorates microvascular pathology in type 2 diabetic mice

Human induced pluripotent stem cells (hiPSCs) were differentiated into a specific mesoderm subset characterized by KDR+CD56+APLNR+ (KNA+) expression. KNA+ cells had high clonal proliferative potential and specification into endothelial colony-forming cell (ECFCs) phenotype. KNA+ cells differentiated into perfused blood vessels when implanted subcutaneously into the flank of nonobese diabetic/severe combined immunodeficient mice and when injected into the vitreous of type 2 diabetic mice (db/db mice). Transcriptomic analysis showed that differentiation of hiPSCs derived from diabetics into KNA+ cells was sufficient to change baseline differences in gene expression caused by the diabetic status and reprogram diabetic cells to a pattern similar to KNA+ cells derived from nondiabetic hiPSCs. Proteomic array studies performed on retinas of db/db mice injected with either control or diabetic donor-derived KNA+ cells showed correction of aberrant signaling in db/db retinas toward normal healthy retina. These data provide "proof of principle" that KNA+ cells restore perfusion and correct vascular dysfunction in db/db mice.

Recent development of BTK-based dual inhibitors in the treatment of cancers

Bruton's tyrosine kinase (BTK) is a promising target in the treatment of various cancers. Despite the early success of BTK inhibitors in the clinic, these single-target drug therapies have limitations in their clinical applications, such as drug resistance. Several alternative strategies have been developed, including the use of dual inhibitors, to maximize the therapeutic potential of anticancer drugs. In this review, we highlight the scientific background and theoretical basis for developing BTK-based dual inhibitors, as well as the status of these agents in preclinical and clinical studies, and discuss further options in this field. We posit that these advances in BTK-based dual inhibitors confirm their feasibility for the treatment of refractory tumors, including those with drug resistance, and provide a framework for future drug design in this field. Accordingly, we anticipate increasingly rapid progress in the development of novel potent dual inhibitors and advanced clinical research on BTK-based dual inhibitors.

A multiscale cell-based model of tumor growth for chemotherapy assessment and tumor-targeted therapy through a 3D computational approach

OBJECTIVES

Computational modeling of biological systems is a powerful tool to clarify diverse processes contributing to cancer. The aim is to clarify the complex biochemical and mechanical interactions between cells, the relevance of intracellular signaling pathways in tumor progression and related events to the cancer treatments, which are largely ignored in previous studies.

MATERIALS AND METHODS

A three-dimensional multiscale cell-based model is developed, covering multiple time and spatial scales, including intracellular, cellular, and extracellular processes. The model generates a realistic representation of the processes involved from an implementation of the signaling transduction network.

RESULTS

Considering a benign tumor development, results are in good agreement with the experimental ones, which identify three different phases in tumor growth. Simulating tumor vascular growth, results predict a highly vascularized tumor morphology in a lobulated form, a consequence of cells' motile behavior. A novel systematic study of chemotherapy intervention, in combination with targeted therapy, is presented to address the capability of the model to evaluate typical clinical protocols. The model also performs a dose comparison study in order to optimize treatment efficacy and surveys the effect of chemotherapy initiation delays and different regimens.

CONCLUSIONS

Results not only provide detailed insights into tumor progression, but also support suggestions for clinical implementation. This is a major step toward the goal of predicting the effects of not only traditional chemotherapy but also tumor-targeted therapies.

Rapamycin, Acarbose and 17α-estradiol share common mechanisms regulating the MAPK pathways involved in intracellular signaling and inflammation

BACKGROUND

Rapamycin (Rapa), acarbose (ACA), and 17α-estradiol (17aE2, males only) have health benefits that increase lifespan of mice. Little is known about how these three agents alter the network of pathways downstream of insulin/IGF1 signals as well as inflammatory/stress responses.

RESULTS

ACA, Rapa, and 17aE2 (in males, but not in females) oppose age-related increases in the MEK1- ERK1/2-MNK1/2 cascade, and thus reduce phosphorylation of eIF4E, a key component of cap-dependent translation. In parallel, these treatments (in both sexes) reduce age-related increases in the MEK3-p38MAPK-MK2 pathway, to decrease levels of the acute phase response proteins involved in inflammation.

CONCLUSION

Each of three drugs converges on the regulation of both the ERK1/2 signaling pathway and the p38-MAPK pathway. The changes induced by treatments in ERK1/2 signaling are seen in both sexes, but the 17aE2 effects are male-specific, consistent with the effects on lifespan. However, the inhibition of age-dependent p38MAPK pathways and acute phase responses is triggered in both sexes by all three drugs, suggesting new approaches to prevention or reversal of age-related inflammatory changes in a clinical setting independent of lifespan effects.

Potential therapies for immune-related adverse events associated with immune checkpoint inhibition: from monoclonal antibodies to kinase inhibition

The therapeutic benefits of immune checkpoint inhibitors (ICIs), which enable antitumor immune responses, can be tempered by unwanted immune-related adverse events (irAEs). Treatment recommendations stratified by irAE phenotype and immunohistopathological findings have only recently been proposed and are often based on those used in primary autoimmune diseases, including targeting of specific proinflammatory cytokines with monoclonal antibodies. Increasing evidence supports the use of such antibody-based strategies as effective steroid-sparing treatments, although the therapies themselves may be associated with additional drug toxicities and reduced ICI efficacy. Kinases are key contributors to the adaptive and innate responses that drive primary autoimmune diseases and irAEs. The janus kinase/signal transducer and activator of transcription, Bruton’s tyrosine kinase, and mitogen-activated protein kinase-interacting serine/threonine protein kinases 1 and 2 pathways are also critical to tumor progression and have important roles in cells of the tumor microenvironment. Herein, we review the histopathological, biological, and clinical evidence to support specific monoclonal antibodies and kinase inhibition as management strategies for irAEs.

JAK2 inhibitor persistence in MPN: uncovering a central role of ERK activation

The Philadelphia chromosome negative myeloproliferative neoplasms, including polycythemia vera, essential thrombocytosis, and myelofibrosis, are driven by hyper activation of the JAK2 tyrosine kinase, the result of mutations in three MPN driving genes: JAK2, MPL, and CALR. While the anti-inflammatory effects of JAK2 inhibitors can provide improved quality of life for many MPN patients, the upfront and persistent survival of disease-driving cells in MPN patients undergoing JAK2 inhibitor therapy thwarts potential for remission. Early studies indicated JAK2 inhibitor therapy induces heterodimeric complex formation of JAK2 with other JAK family members leading to sustained JAK2-dependent signaling. Recent work has described novel cell intrinsic details as well as cell extrinsic mechanisms that may contribute to why JAK2 inhibition may be ineffective at targeting MPN driving cells. Diverse experimental strategies aimed at uncovering mechanistic details that contribute to JAK2 inhibitor persistence have each highlighted the role of MEK/ERK activation. These approaches include, among others, phosphoproteomic analyses of JAK2 signaling as well as detailed assessment of JAK2 inhibition in mouse models of MPN. In this focused review, we highlight these and other studies that collectively suggest targeting MEK/ERK in combination with JAK2 inhibition has the potential to improve the efficacy of JAK2 inhibitors in MPN patients. As MPN patients patiently wait for improved therapies, such studies should further strengthen optimism that pre-clinical research is continuing to uncover mechanistic insights regarding the ineffectiveness of JAK2 inhibitors, which may lead to development of improved therapeutic strategies.

The Cap-Binding Complex CBC and the Eukaryotic Translation Factor eIF4E: Co-Conspirators in Cap-Dependent RNA Maturation and Translation

The translation of RNA into protein is a dynamic process which is heavily regulated during normal cell physiology and can be dysregulated in human malignancies. Its dysregulation can impact selected groups of RNAs, modifying protein levels independently of transcription. Integral to their suitability for translation, RNAs undergo a series of maturation steps including the addition of the m7G cap on the 5' end of RNAs, splicing, as well as cleavage and polyadenylation (CPA). Importantly, each of these steps can be coopted to modify the transcript signal. Factors that bind the m7G cap escort these RNAs through different steps of maturation and thus govern the physical nature of the final transcript product presented to the translation machinery. Here, we describe these steps and how the major m7G cap-binding factors in mammalian cells, the cap binding complex (CBC) and the eukaryotic translation initiation factor eIF4E, are positioned to chaperone transcripts through RNA maturation, nuclear export, and translation in a transcript-specific manner. To conceptualize a framework for the flow and integration of this genetic information, we discuss RNA maturation models and how these integrate with translation. Finally, we discuss how these processes can be coopted by cancer cells and means to target these in malignancy.

Optimization of 4,6-Disubstituted Pyrido[3,2-d]pyrimidines as Dual MNK/PIM Inhibitors to Inhibit Leukemia Cell Growth

Mitogen-activated protein kinase-interacting kinases (MNKs) and provirus integration in maloney murine leukemia virus kinases (PIMs) are downstream enzymes of cell proliferation signaling pathways associated with the resistance of tyrosine kinase inhibitors. MNKs and PIMs have complementary effects to regulate cap-dependent translation of oncoproteins. Dual inhibitors of MNKs and PIMs have not been developed. We developed a novel 4,6-disubstituted pyrido[3,2-d]pyrimidine compound 21o with selective inhibition of MNKs and PIMs. The IC50's of 21o to inhibit MNK1 and MNK2 are 1 and 7 nM and those to inhibit PIM1, PIM2, and PIM3 are 43, 232, and 774 nM, respectively. 21o inhibits the growth of myeloid leukemia K562 and MOLM-13 cells with GI50's of 2.1 and 1.2 μM, respectively. 21o decreases the levels of p-eIF4E and p-4EBP1, the downstream products of MNKs and PIMs, as well as cap-dependent proteins c-myc, cyclin D1, and Mcl-1. 21o inhibits the growth of MOLM-13 cell xenografts without causing evident toxicity. 21o represents an innovative dual MNK/PIM inhibitor with a good pharmacokinetic profile.

Update on the Development of MNK Inhibitors as Therapeutic Agents

Mitogen-activated protein kinase-interacting kinases 1 and 2 (MNK1/2) represent a central class of enzymes that are activated by extracellular signal-regulated kinase (ERK) or p38 mitogen-activated protein (MAP) kinases. MNK1 and MNK2 coordinate cellular signaling, control production of inflammatory chemokines, and regulate cell proliferation and survival. MNK1/2 are referred to as serine/threonine kinases as they phosphorylate serine or threonine residues on their substrates. Upon activation, MNK1/2 phosphorylate eukaryotic translation initiation factor 4E (eIF4E) at Ser209, which in turn initiates ribosome assembly and protein translation. Deleterious overexpression of MNK1/2 and/or eIF4E have been reported in several diseases including cancers, neurological disorders, autism, and inflammation. Recently, there have been intense efforts toward the development of potent and selective inhibitors of MNK1/2 in both academia and industry. Herein, we review the current understanding of the structural and biological aspects of MNK1/2 and provide an update of pharmacological inhibitors of MNK1/2 including candidates in clinical trials.

Study of chondroitin sulfate E oligosaccharide as a promising complement C5 inhibitor for osteoarthritis alleviation

Osteoarthritis (OA) is a degenerative joint disease which is highly prevalent worldwide. However, no therapy for blocking OA pathogenesis is available currently. In this study, chondroitin sulfate (CS) E oligosaccharides were prepared and we identified disaccharide as the functional unit showing the strongest anti-complement activity and screened out complement C5 as its target in the complement system. We determined that CS-E disaccharide produced anti-inflammatory effects to treat OA by regulating the complement system: it inhibited the formation of complement-dependent complexes such as the membrane-attack complex (MAC) by targeting C5 and suppressed MAC-induced protein expression and the activation of downstream MAPK and NF-κB signaling pathways accordingly. By identifying CS-E disaccharide which could be regarded as a complement regulator or inhibitor exhibiting high anti-complement activity and revealing its OA-alleviating mechanism, this study not only provides a new strategy for OA treatment and drug development, but also potentially offers a promising C5 target therapy for other associated diseases.

Multiscale modeling of tumor growth and angiogenesis: Evaluation of tumor-targeted therapy

The dynamics of tumor growth and associated events cover multiple time and spatial scales, generally including extracellular, cellular and intracellular modifications. The main goal of this study is to model the biological and physical behavior of tumor evolution in presence of normal healthy tissue, considering a variety of events involved in the process. These include hyper and hypoactivation of signaling pathways during tumor growth, vessels' growth, intratumoral vascularization and competition of cancer cells with healthy host tissue. The work addresses two distinctive phases in tumor development-the avascular and vascular phases-and in each stage two cases are considered-with and without normal healthy cells. The tumor growth rate increases considerably as closed vessel loops (anastomoses) form around the tumor cells resulting from tumor induced vascularization. When taking into account the host tissue around the tumor, the results show that competition between normal cells and cancer cells leads to the formation of a hypoxic tumor core within a relatively short period of time. Moreover, a dense intratumoral vascular network is formed throughout the entire lesion as a sign of a high malignancy grade, which is consistent with reported experimental data for several types of solid carcinomas. In comparison with other mathematical models of tumor development, in this work we introduce a multiscale simulation that models the cellular interactions and cell behavior as a consequence of the activation of oncogenes and deactivation of gene signaling pathways within each cell. Simulating a therapy that blocks relevant signaling pathways results in the prevention of further tumor growth and leads to an expressive decrease in its size (82% in the simulation).

Dioscorea Zingiberensis New Saponin Inhibits the Growth of Hepatocellular Carcinoma by Suppressing the Expression of Long Non-coding RNA TCONS-00026762

Background: The etiology and carcinogenesis of hepatocellular carcinoma (HCC) are associated with various risk factors. Saponins extracted from Dioscorea zingiberensis C. H. Wright exhibit antitumor activity against HCC. This study aimed to investigate the effect and the underlying mechanism of Dioscorea Zingiberensis new saponin (ZnS) on HCC. Methods: Human HCC cell lines, Huh7 and SMMC-7721, were treated with different concentrations of ZnS. Cell apoptosis was determined via flow cytometry assay. Differentially expressed lncRNAs (DElncRNAs) in ZnS-treated SMMC-7721 cells were determined through RNA-sequence. The role of lncRNA TCONS-00026762 in HCC was investigated gain of function analysis, along with cell proliferation, apoptosis, and invasion in HCC cells. A subcutaneous xenograft of SMMC-7721 cell lines was established to study the effects of TCONS-00026762 in vivo. The expression of apoptosis-related proteins was detected in vivo and in vitro via western blotting. Results: ZnS inhibited the proliferation of HCC cell in a dose-dependent manner. ZnS could induce apoptosis in HCC cells. Illumina sequencing results showed that 493 DElncRNAs were identified in ZnS-treated SMMC-7721 cells. TCONS-00026762 expression was down-regulated in the ZnS-treated SMMC-7721 cells. TCONS-00026762 inhibited the effect of ZnS on the proliferation, apoptosis, and invasion of HCC cells. ZnS inhibited the tumor growth, while, TCONS-00026762 promoted tumor growth in vivo. Furthermore, ZnS and TCONS-00026762 regulated cell apoptotic pathways. Conclusion: ZnS significantly inhibits the viability, apoptosis, invasion, and tumorigenicity of HCC cells by regulating the expression of TCONS-00026,762. Our findings provide novel insights into the potential role of lncRNA in HCC therapy.

Stress-activated protein kinases are involved in the replication of porcine deltacoronavirus

This study was conducted to examine the role of stress-activated protein kinases (SAPKs), including c-Jun NH₂-terminal kinases (JNK1/2) and p38 mitogen-activated protein kinase (MAPK), in porcine deltacoronavirus (PDCoV) infection. Results demonstrated the activation of JNK1/2 and p38 MAPK in PDCoV-infected cells, which occurred concomitant with viral biosynthesis and irrespective of cell type. Pharmacological inhibition or knockdown of either SAPK significantly attenuated PDCoV replication, whereas addition of a signaling activator augmented virus infectivity. Moreover, pharmacological inhibition of JNK1/2 or p38 MAPK activation was innocuous to viral entry but significantly detrimental to post uncoating stages of the replication cycle. Remarkably, cytokine gene expression in PDCoV-infected IPEC-J2 cells was modified by inhibiting the activation of either SAPK. Collectively, these data indicate that JNK1/2 and p38 MAPK signaling pathways contribute to viral biosynthesis and regulate immune responses, thereby favoring the replication of PDCoV.

Progress in developing MNK inhibitors

The MNKs (mitogen-activated protein kinase-interacting protein kinases) phosphorylate eIF4E (eukaryotic initiation factor 4 E) at serine 209; eIF4E plays an important role in the translation of cytoplasmic mRNAs, all of which possess a 5' 'cap' structure to which eIF4E binds. Elevated levels of eIF4E, p-eIF4E and/or the MNK protein kinases have been found in many types of cancer, including solid tumors and leukemia. MNKs also play a role in metabolic disease. Regulation of the activities of MNKs (MNK1 and MNK2), control the phosphorylation of eIF4E, which in turn has a close relationship with the processes of tumor development, cell migration and invasion, and energy metabolism. MNK knock-out mice display no adverse effects on normal cells or phenotypes suggesting that MNK may be a potentially safe targets for the treatment of various cancers. Several MNK inhibitors or 'degraders' have been identified. Initially, some of the inhibitors were developed from natural products or based on other protein kinase inhibitors which inhibit multiple kinases. Subsequently, more potent and selective inhibitors for MNK1/2 have been designed and synthesized. Currently, three inhibitors (BAY1143269, eFT508 and ETC-206) are in various stages of clinical trials for the treatment of solid cancers or leukemia, either alone or combined with inhibitors of other protein kinase. In this review, we summarize the diverse MNK inhibitors that have been reported in patents and other literature, including those with activities in vitro and/or in vivo.

MNK as a potential pharmacological target for suppressing LPS-induced acute lung injury in mice

Acute lung injury (ALI) or its more severe form, known as acute respiratory distress syndrome (ARDS), is characterized by an initial exudative phase, expression of proinflammatory mediators, activation of inflammatory leukocytes, and impairment of the lung endothelium and epithelium. Despite numerous, novel therapeutic strategies have been developed regarding the pathophysiology of ALI, current treatment is mainly supportive, as specific therapies have not been established in the past few decades. The MAP kinase-interacting kinases (MNK1 and MNK2) are serine threonine kinases which are activated by mitogen-activated protein kinases (MAPKs), regulate protein synthesis by phosphroylating eukaryotic translation initiation factor 4E (eIF4E). Although studies have shown that MAPKs pathway is involved in anti-inflammatory and preventing tissue injury processes, the role of MNKs in ALI has, until now, remained relatively unexplored. Here, we investigated whether partial inhibition of MAPKs pathway by targeting MNKs was effective in the prevention and treatment of ALI. C57BL6 mice were pretreated with MNK1 and MNK2 inhibitor (CGP57380, 30 mg/kg) for 30 min and then challenged with 5 mg/kg LPS for 6 h. The results showed that pretreatment with CGP57380 not only significantly attenuated LPS-induced lung wet/dry ratio, as well as protein content, total cells and neutrophils in bronchoalveolar lavage fluid (BALF), but also decreased the production of pro-inflammatory mediators such as interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α) and keratinocyte-derived chemoattractant (KC). In addition, CGP57380 was observed to significantly suppress LPS-stimulated phosphorylation of eIF4E and MAPKs in the mouse bone marrow-derived macrophages (BMDMs). The involvement of MNK2 in lung injury was further evident by MNK2 knockout mice. MNK2 deficiency resulted in the attenuated lung histopathological changes, as also reflected by reductions in neutrophil counts, and the less LPS-induced the production of IL-6, TNF-α and KC in mouse BALF. Taken together, these findings demonstrated for the first time that MNK inhibition could effectively reduce the LPS-induced ALI in mice, suggesting a novel and potential application for MNK-based therapy to treat this serious disease.

SNPs within microRNA binding sites and the prognosis of breast cancer

Single nucleotide polymorphisms (SNPs) within microRNA binding sites can affect the binding of microRNA to mRNA and regulate gene expression, thereby contributing to cancer prognosis. Here we performed a two-stage study of 2647 breast cancer patients to explore the association between SNPs within microRNA binding sites and breast cancer prognosis. In stage I, we genotyped 192 SNPs within microRNA binding sites using the Illumina Goldengate platform. In stage II, we validated SNPs associated with breast cancer prognosis in another dataset using the TaqMan platform. We identified 8 SNPs significantly associated with breast cancer prognosis in stage I (P<0.05), and only rs10878441 was statistically significant in stage II (AA vs CC, HR=2.21, 95% CI: 1.11-4.42, P=0.024). We combined the data from stage I and stage II, and found that, compared with rs10878441 AA genotype, CC genotype was associated with poor survival of breast cancer (HR=2.19, 95% CI: 1.30-3.70, P=0.003). Stratified analyses demonstrated that rs10878441 was related to breast cancer prognosis in grade II and lymph node-negative patients (P<0.05). The Leucine-rich repeat kinase 2 (LRRK2) rs10878441 CC genotype is associated with poor prognosis of breast cancer in a Chinese population and may be used as a potential prognostic biomarker for breast cancer.

• The LRRK2 rs10878441 CC genotype is associated with poor prognosis of breast cancer in a Chinese population.

• Stratified analyses demonstrated that rs10878441 was related to breast cancer prognosis in grade II patients and lymph node-negative patients.

Diversity and versatility of p38 kinase signalling in health and disease

The ability of cells to deal with different types of stressful situations in a precise and coordinated manner is key for survival and involves various signalling networks. Over the past 25 years, p38 kinases — in particular, p38α — have been implicated in the cellular response to stress at many levels. These span from environmental and intracellular stresses, such as hyperosmolarity, oxidative stress or DNA damage, to physiological situations that involve important cellular changes such as differentiation. Given that p38α controls a plethora of functions, dysregulation of this pathway has been linked to diseases such as inflammation, immune disorders or cancer, suggesting the possibility that targeting p38α could be of therapeutic interest. In this Review, we discuss the organization of this signalling pathway focusing on the diversity of p38α substrates, their mechanisms and their links to particular cellular functions. We then address how the different cellular responses can be generated depending on the signal received and the cell type, and highlight the roles of this kinase in human physiology and in pathological contexts.

p38α — the best-characterized member of the p38 kinase family — is a key mediator of cellular stress responses. p38α is activated by a plethora of signals and functions through a multitude of substrates to regulate different cellular behaviours. Understanding context-dependent p38α signalling provides important insights into p38α roles in physiology and pathology.

Discovery of indazole-pyridinone derivatives as a novel class of potent and selective MNK1/2 kinase inhibitors that protecting against endotoxin-induced septic shock

The mitogen-activated protein kinase (MAPK)-interacting kinases 1 and 2 (MNKs 1/2) and their downstream target eIF4E, play a role in oncogenic transformation, progression and metastasis. These results provided rationale for development of first MNKs inhibitors, currently in clinical trials for cancer treatment. Inhibitors of the MNKs/eIF4E pathway are also proposed as treatment strategy for inflammatory conditions. Here we present results of optimization of indazole-pyridinone derived MNK1/2 inhibitors among which compounds 24 and 26, selective and metabolically stable derivatives. Both compounds decreased levels of eIF4E Ser206 phosphorylation (pSer209-eIF4E) in MOLM16 cell line. When administered in mice compounds 24 and 26 significantly improved survival rates of animals in the endotoxin lethal dose challenge model, with concomitant reduction of proinflammatory cytokine levels - TNFα and IL-6 in serum. Identified MNK1/2 inhibitors represent a novel class of immunomodulatory compounds with a potential for the treatment of inflammatory diseases including sepsis.

The role of cap-dependent translation in aged-related changes in neuroimmunity and affective behaviors

Translation regulation in the context of aged-associated inflammation and behavioral impairments is not well characterized. Aged individuals experience lower life quality due to behavioral impairments. In this study, we used young and aged transgenic mice that are unable to activate the cap-binding protein, eukaryotic translation initiation factor 4E (eIF4E) to examine the role of protein translation control in aging, memory, depression, and anxiety. To determine how products of cap-dependent translation play a permissive role in aged-associated inflammation, we assessed levels of pro-inflammatory cytokines in various brain regions involved in the above-mentioned behaviors. We found that functional eIF4E is not necessary for age-related deficits in spatial and short-term memory but is important for depressive and anxiety-like behavior and this is correlated with pro-inflammatory cytokines in discrete brain regions. Thus, we have begun to elucidate a role for eIF4E phosphorylation in the context of aged-related behavioral impairments and chronic low-grade inflammation that may help identify novel immune modulators for therapeutic targets and decrease the burden of self-care among the geriatric population.