A potent MAPK13-14 inhibitor prevents airway inflammation and mucus production.

Common respiratory diseases continue to represent a major public health problem, and much of the morbidity and mortality is due to airway inflammation and mucus production. Previous studies indicated a role for mitogen-activated protein kinase 14 (MAPK14) in this type of disease, but clinical trials are unsuccessful to date. Our previous work identified a related but distinct kinase known as MAPK13 that is activated in respiratory airway diseases and is required for mucus production in human cell-culture models. Support for MAPK13 function in these models came from effectiveness of MAPK13 versus MAPK14 gene-knockdown and from first-generation MAPK13-14 inhibitors. However, these first-generation inhibitors were incompletely optimized for blocking activity and were untested in vivo. Here we report the next generation and selection of a potent MAPK13-14 inhibitor (designated NuP-3) that more effectively downregulates type-2 cytokine-stimulated mucus production in air-liquid interface and organoid cultures of human airway epithelial cells. We also show that NuP-3 treatment prevents respiratory airway inflammation and mucus production in new minipig models of airway disease triggered by type-2 cytokine challenge or respiratory viral infection. The results thereby provide the next advance in developing a small-molecule kinase inhibitor to address key features of respiratory disease.NEW & NOTEWORTHY This study describes the discovery of a potent mitogen-activated protein kinase 13-14 (MAPK13-14) inhibitor and its effectiveness in models of respiratory airway disease. The findings thereby provide a scheme for pathogenesis and therapy of lung diseases [e.g., asthma, chronic obstructive pulmonary disease (COPD), Covid-19, postviral, and allergic respiratory disease] and related conditions that implicate MAPK13-14 function. The findings also refine a hypothesis for epithelial and immune cell functions in respiratory disease that features MAPK13 as a possible component of this disease process.

Identification and overcoming rituximab resistance in diffuse large B-cell lymphoma using next-generation sequencing.

BACKGROUND/AIMS: Although rituximab, an antiCD20 monoclonal antibody, has dramatically improved the clinical outcomes of diffuse large B-cell lymphoma, rituximab resistance remains a challenge. METHODS: We developed a rituximab-resistant cell line (RRCL) by sequential exposure to gradually increasing concentrations of rituximab in a rituximab-sensitive cell line (RSCL). When the same dose of rituximab was administered, RRCL showed a smaller decrease in cell viability and apoptosis than RSCL. To determine the differences in gene expression between RSCL and RRCL, we performed next-generation sequencing. RESULTS: In total, 1,879 differentially expressed genes were identified, and in the over-representation analysis of Consensus-PathDB, mitogen-activated protein kinase (MAPK) signaling pathway showed statistical significance. MAPK13, which encodes the p38δ protein, was expressed more than four-fold in RRCL. Western blot analysis revealed that phosphop38 expression mainwas increased in RRCL, and when p38 inhibitor was administered, phosphop38 expression was significantly decreased. Therefore, we hypothesized that p38 MAPK activation was associated with rituximab resistance. Previous studies have suggested that p38 is associated with NF-κB activation. Deferasirox has been reported to inhibit NF-κB activity and suppress phosphorylation of the MAPK pathway. Furthermore, it also has cytotoxic effects on various cancers and synergistic effects in overcoming drug resistance. In this study, we confirmed that deferasirox induced dose-dependent cytotoxicity in both RSCL and RRCL, and the combination of deferasirox and rituximab showed a synergistic effect in RRCL at all combination concentrations. CONCLUSION: We suggest that p38 MAPK, especially p38δ, activation is associated with rituximab resistance, and deferasirox may be a candidate to overcome rituximab resistance.

p38γ and p38δ modulate innate immune response by regulating MEF2D activation.

Evidence implicating p38γ and p38δ (p38γ/p38δ) in inflammation are mainly based on experiments using Mapk12/Mapk13-deficient (p38γ/δKO) mice, which show low levels of TPL2, the kinase upstream of MKK1-ERK1/2 in myeloid cells. This could obscure p38γ/p38δ roles, since TPL2 is essential for regulating inflammation. Here, we generated a Mapk12D171A/D171A/Mapk13-/- (p38γ/δKIKO) mouse, expressing kinase-inactive p38γ and lacking p38δ. This mouse exhibited normal TPL2 levels, making it an excellent tool to elucidate specific p38γ/p38δ functions. p38γ/δKIKO mice showed a reduced inflammatory response and less susceptibility to lipopolysaccharide (LPS)-induced septic shock and Candida albicans infection than wild-type (WT) mice. Gene expression analyses in LPS-activated wild-type and p38γ/δKIKO macrophages revealed that p38γ/p38δ-regulated numerous genes implicated in innate immune response. Additionally, phospho-proteomic analyses and in vitro kinase assays showed that the transcription factor myocyte enhancer factor-2D (MEF2D) was phosphorylated at Ser444 via p38γ/p38δ. Mutation of MEF2D Ser444 to the non-phosphorylatable residue Ala increased its transcriptional activity and the expression of Nos2 and Il1b mRNA. These results suggest that p38γ/p38δ govern innate immune responses by regulating MEF2D phosphorylation and transcriptional activity.

P38 kinase in gastrointestinal cancers.

Gastrointestinal cancers are a leading cause of cancer morbidity and mortality worldwide with 4.2 million new cases and 3.2 million deaths estimated in 2020. Despite the advances in primary and adjuvant therapies, patients still develop distant metastases and require novel therapies. Mitogen­activated protein kinase (MAPK) cascades are crucial signaling pathways that regulate many cellular processes, including proliferation, differentiation, apoptosis, stress responses and cancer development. p38 Mitogen Activated Protein Kinases (p38 MAPKs) includes four isoforms: p38α (MAPK14), p38ß (MAPK11), p38γ (MAPK12), and p38δ (MAPK13). p38 MAPK was first identified as a stress response protein kinase that phosphorylates different transcriptional factors. Dysregulation of p38 pathways, in particular p38γ, are associated with cancer development, metastasis, autophagy and tumor microenvironment. In this article, we provide an overview of p38 and p38γ with respect to gastrointestinal cancers. Furthermore, targeting p38γ is also discussed as a potential therapy for gastrointestinal cancers.

Immunoregulatory actions of calf thymus extract (TFX®) in vitro in relation to its effect on expression of mitogen activated protein kinases.

The in vitro immunotropic actions of a calf thymus extract - thymus factor X (TFX®) preparation were investigated. The preparation did not lower the viability of the A549 epithelial cell line and mouse bone marrow cells in the investigated concentration range. TFX® exhibited a co-stimulatory action of concanavalin A (Con A)-induced mouse thymocyte proliferation and partially restored the mitogen-induced proliferation capability of mouse thymocytes exposed to hydrocortisone (HC). The preparation also inhibited Herpes virus-1 (HSV-1) replication in A549 cells when preincubated with the virus and when added to the infected cells. In addition, it weakly inhibited lipopolysaccharide (LPS)-induced TNF α, IL-1ß and IL-6 by the THP-1 monocyte cell line. The determination of mitogen activated protein kinase (MAPK) expression in Jurkat T cells revealed strong increases in ERK-2 kinase and p38α subunits. In WEHI 231 immature B cells, TFX® elevated p38α, and had a particularly strong elevating effect on p38γ. In HL-60 myeloblastic cells, the expression of p38α, ß and γ was not detectable, almost blocked for p38δ and JNK, but accompanied by an increase in ERK-1. In turn, the effects of TFX® in J744E macrophages resulted in a strong increase in p38γ expression, moderate elevations of ERK and a drop in p38δ. Significant increases in MAPK expression were also found in cells from the lymphoid organs. In the bone marrow cell population, p38α, ß and γ, in thymocytes p38α, γ and δ, and in splenocytes p38ß and γ, subunit expression was elevated. We conclude that the changes in MAPK expression may be attributed to cell maturation and differentiation, and explain the beneficial therapeutic effects of TFX®.

MKK6 deficiency promotes cardiac dysfunction through MKK3-p38γ/δ-mTOR hyperactivation.

Stress-activated p38 kinases control a plethora of functions, and their dysregulation has been linked to the development of steatosis, obesity, immune disorders, and cancer. Therefore, they have been identified as potential targets for novel therapeutic strategies. There are four p38 family members (p38α, p38ß, p38γ, and p38δ) that are activated by MKK3 and MKK6. Here, we demonstrate that lack of MKK6 reduces the lifespan in mice. Longitudinal study of cardiac function in MKK6 KO mice showed that young mice develop cardiac hypertrophy which progresses to cardiac dilatation and fibrosis with age. Mechanistically, lack of MKK6 blunts p38α activation while causing MKK3-p38γ/δ hyperphosphorylation and increased mammalian target of rapamycin (mTOR) signaling, resulting in cardiac hypertrophy. Cardiac hypertrophy in MKK6 KO mice is reverted by knocking out either p38γ or p38δ or by inhibiting the mTOR pathway with rapamycin. In conclusion, we have identified a key role for the MKK3/6-p38γ/δ pathway in the development of cardiac hypertrophy, which has important implications for the clinical use of p38α inhibitors in the long-term treatment since they might result in cardiotoxicity.

The human heart can increase its size to supply more blood to the body's organs. This process, called hypertrophy, can happen during exercise or be caused by medical conditions, such as high blood pressure or inherited genetic diseases. If hypertrophy is continually driven by illness, this can cause the heart to fail and no longer be able to properly pump blood around the body. For hypertrophy to happen, several molecular changes occur in the cells responsible for contracting the heart, including activation of the p38 pathway. Within this pathway is a p38 enzyme as well as a series of other proteins which are sequentially turned on in response to stress, such as inflammatory molecules or mechanical forces that alter the cell's shape. There are different types of p38 enzyme which have been linked to other diseases, making them a promising target for drug development. However, clinical trials blocking individual members of the p38 family have had disappointing results. An alternative approach is to target other proteins involved in the p38 pathway, such as MKK6, but it is not known what effect this might have. To investigate, Romero-Becerra et al. genetically modified mice to not have any MKK6 protein. As a result, these mice had a shorter lifespan, with hypertrophy developing at a young age that led to heart problems. Romero-Becerra et al. used different mice models to understand why this happened, showing that a lack of MKK6 reduces the activity of a specific member of the p38 family called p38α. However, this blockage boosted a different branch of the pathway which involved two other p38 proteins, p38γ and p38δ. This, in turn, triggered another key pathway called mTOR which also promotes hypertrophy of the heart. These results suggest that drugs blocking MKK6 and p38α could lead to side effects that cause further harm to the heart. A more promising approach for treating hypertrophic heart conditions could be to inhibit p38γ and/or p38δ. However, before this can be fully explored, further work is needed to generate compounds that specifically target these proteins.

TPL2 kinase expression is regulated by the p38γ/p38δ-dependent association of aconitase-1 with TPL2 mRNA.

p38γ and p38δ (p38γ/p38δ) regulate inflammation, in part by controlling tumor progression locus 2 (TPL2) expression in myeloid cells. Here, we demonstrate that TPL2 protein levels are dramatically reduced in p38γ/p38δ-deficient (p38γ/δ-/-) cells and tissues without affecting TPL2 messenger ribonucleic acid (mRNA) expression. We show that p38γ/p38δ posttranscriptionally regulates the TPL2 amount at two different levels. p38γ/p38δ interacts with the TPL2/A20 Binding Inhibitor of NF-κB2 (ABIN2)/Nuclear Factor κB1p105 (NF-κB1p105) complex, increasing TPL2 protein stability. Additionally, p38γ/p38δ regulates TPL2 mRNA translation by modulating the repressor function of TPL2 3' Untranslated region (UTR) mediated by its association with aconitase-1 (ACO1). ACO1 overexpression in wild-type cells increases the translational repression induced by TPL2 3'UTR and severely decreases TPL2 protein levels. p38δ binds to ACO1, and p38δ expression in p38γ/δ-/- cells fully restores TPL2 protein to wild-type levels by reducing the translational repression of TPL2 mRNA. This study reveals a unique mechanism of posttranscriptional regulation of TPL2 expression, which given its central role in innate immune response, likely has great relevance in physiopathology.

Identification and characterization of inhibitory nanobody against p38δ.

p38δ is a member of p38 mitogen-activated protein kinases (MAPKs) family that displays cell- and tissue-specific expression patterns. Recent studies demonstrate that p38δ is centrally involved in several pathologic events, such as diabetes, neurodegeneration diseases, inflammatory diseases, and cancer, and suggest that it may be a potential target for diagnosis and therapy of specific diseases. A nanobody is a new type of antibody that exhibits high antigen-binding activity, solubility, stability, and easy production. This study utilized phage display to isolate nanobodies specifically against p38δ from a fully synthetic nanobody library. Two of them, nanobodies Nb13-6 and Nb13-1, display high binding activity to p38δ, less cross-reactivity with other p38 MAPKs, and high thermal and pH stabilities. Modeling and docking analysis indicated that Nb13-6 is mostly linked to the activation loop of p38δ. Furthermore, detailed studies revealed that Nb13-6 inhibited the protein kinase activity of p38δ and the growth of cancer cells. Therefore, this study provides p38δ-specific nanobodies that are promisingly exploited for diagnosing and treating p38δ-associated diseases.

The role of MAPK11/12/13/14 (p38 MAPK) protein in dopamine agonist-resistant prolactinomas.

BACKGROUND: Prolactinoma is a functional pituitary adenoma that secretes excessive prolactin. Dopamine agonists (DAs) such as bromocriptine (BRC) are the first-line treatment for prolactinomas, but the resistance rate is increasing year by year, creating a clinical challenge. Therefore, it is urgent to explore the molecular mechanism of bromocriptine resistance in prolactinomas. Activation of the P38 MAPK pathway affects multidrug resistance in tumours. Our previous studies have demonstrated that inhibiting MAPK14 can suppress the occurrence of prolactinoma, but the role of MAPK11/12/13/14 (p38 MAPK) signalling in dopamine agonist-resistant prolactinomas is still unclear. METHODS: A prolactinoma rat model was established to determine the effect of bromocriptine on MAPK11/12/13/14 signalling. DA-resistant GH3 cells and DA-sensitive MMQ cells were used, and the role of MAPK11/12/13/14 in bromocriptine-resistant prolactinomas was preliminarily verified by western blot, RT-qPCR, ELISA, flow cytometry and CCK-8 experiments. The effects of MAPK11 or MAPK14 on bromocriptine-resistant prolactinomas were further verified by siRNA transfection experiments. RESULTS: Bromocriptine was used to treat rat prolactinoma by upregulating DRD2 expression and downregulating the expression level of MAPK11/12/13/14 in vivo experiments. The in vitro experiments showed that GH3 cells are resistant to bromocriptine and that MMQ cells are sensitive to bromocriptine. Bromocriptine could significantly reduce the expression of MAPK12 and MAPK13 in GH3 cells and MMQ cells. Bromocriptine could significantly reduce the expression of MAPK11, MAPK14, NF-κB p65 and Bcl2 in MMQ but had no effect on MAPK11, MAPK14, NF-κB p65 and Bcl2 in GH3 cells. In addition, knockdown of MAPK11 and MAPK14 in GH3 cells by siRNA transfection reversed the resistance of GH3 cells to bromocriptine, and haloperidol (HAL) blocked the inhibitory effect of bromocriptine on MAPK14, MAPK11, and PRL in MMQ cells. Our findings show that MAPK11 and MAPK14 proteins are involved in bromocriptine resistance in prolactinomas. CONCLUSION: Bromocriptine reduces the expression of MAPK11/12/13/14 in prolactinomas, and MAPK11 and MAPK14 are involved in bromocriptine resistance in prolactinomas by regulating apoptosis. Reducing the expression of MAPK11 or MAPK14 can reverse bromocriptine resistance in prolactinomas.

p38γ and p38δ regulate postnatal cardiac metabolism through glycogen synthase 1.

During the first weeks of postnatal heart development, cardiomyocytes undergo a major adaptive metabolic shift from glycolytic energy production to fatty acid oxidation. This metabolic change is contemporaneous to the up-regulation and activation of the p38γ and p38δ stress-activated protein kinases in the heart. We demonstrate that p38γ/δ contribute to the early postnatal cardiac metabolic switch through inhibitory phosphorylation of glycogen synthase 1 (GYS1) and glycogen metabolism inactivation. Premature induction of p38γ/δ activation in cardiomyocytes of newborn mice results in an early GYS1 phosphorylation and inhibition of cardiac glycogen production, triggering an early metabolic shift that induces a deficit in cardiomyocyte fuel supply, leading to whole-body metabolic deregulation and maladaptive cardiac pathogenesis. Notably, the adverse effects of forced premature cardiac p38γ/δ activation in neonate mice are prevented by maternal diet supplementation of fatty acids during pregnancy and lactation. These results suggest that diet interventions have a potential for treating human cardiac genetic diseases that affect heart metabolism.

Melatonin improves rate of monospermic fertilization and early embryo development in a bovine IVF system.

The developmental competence of male and female gametes is frequently reduced under in vitro conditions, mainly due to oxidative stress during handling. The amino-acid derived hormone melatonin has emerged as a potent non-enzymatic antioxidant in many biological systems. The goal of the present study was to evaluate the effects of melatonin on post-thaw sperm quality, fertilizing ability, and embryo development and competence in vitro after in vitro fertilization. Frozen-thawed bovine spermatozoa were incubated either in the presence of 10-11 M melatonin (MT), or its solvent (ethanol; Sham-Control), or plain Tyrode's Albumin Lactate Pyruvate medium (TALP, Control). Computer-Assisted Sperm Analysis (CASA) and flow cytometry data after 30 min, 120 min, and 180 min incubation did not reveal any significant effects of melatonin on average motility parameters, sperm subpopulation structure as determined by hierarchical cluster, or on the percentage of viable, acrosome intact sperm, or viable sperm with active mitochondria. Nevertheless, in vitro matured cumulus-oocyte-complexes fertilized with spermatozoa which had been preincubated with 10-11 M melatonin (MT-Sperm) showed higher (P < 0.01) rates of monospermic fertilization, reduced (P < 0.05) polyspermy and enhanced (P < 0.05) embryo development compared to the Control group. Moreover, the relative abundance of MAPK13 in the in vitro-derived blastocysts was greater (P < 0.05) than observed in the Control group. In conclusion, adding melatonin to the sperm-preparation protocol for bovine IVF improved proper fertilization and enhanced embryonic development and competence in vitro.

p38δ genetic ablation protects female mice from anthracycline cardiotoxicity.

The efficacy of an anthracycline antibiotic doxorubicin (DOX) as a chemotherapeutic agent is limited by dose-dependent cardiotoxicity. DOX is associated with activation of intracellular stress signaling pathways including p38 MAPKs. While previous studies have implicated p38 MAPK signaling in DOX-induced cardiac injury, the roles of the individual p38 isoforms, specifically, of the alternative isoforms p38γ and p38δ, remain uncharacterized. We aimed to determine the potential cardioprotective effects of p38γ and p38δ genetic deletion in mice subjected to acute DOX treatment. Male and female wild-type (WT), p38γ-/-, p38δ-/-, and p38γ-/-δ-/- mice were injected with 30 mg/kg DOX and their survival was tracked for 10 days. During this period, cardiac function was assessed by echocardiography and electrocardiography and fibrosis by Picro Sirius Red staining. Immunoblotting was performed to assess the expression of signaling proteins and markers linked to autophagy. Significantly improved survival was observed in p38δ-/- female mice post-DOX relative to WT females, but not in p38γ-/- or p38γ-/-δ-/- male or female mice. The improved survival in DOX-treated p38δ-/- females was associated with decreased fibrosis, increased cardiac output and LV diameter relative to DOX-treated WT females, and similar to saline-treated controls. Structural and echocardiographic parameters were either unchanged or worsened in all other groups. Increased autophagy, as suggested by increased LC3-II level, and decreased mammalian target of rapamycin activation was also observed in DOX-treated p38δ-/- females. p38δ plays a crucial role in promoting DOX-induced cardiotoxicity in female mice by inhibiting autophagy. Therefore, p38δ targeting could be a potential cardioprotective strategy in anthracycline chemotherapy.NEW & NOTEWORTHY This study for the first time identifies the sex-specific roles of the alternative p38γ and p38δ MAPK isoforms in promoting doxorubicin (DOX) cardiotoxicity. We show that p38δ and p38γ/δ systemic deletion was cardioprotective in female but not in male mice. Cardiac structure and function were preserved in DOX-treated p38δ-/- females and autophagy marker was increased.

Biochanin A impedes STAT3 activation by upregulating p38δ MAPK phosphorylation in IL-6-stimulated macrophages.

OBJECTIVE: IL-6-induced STAT3 activation is associated with various chronic inflammatory diseases. In this study, we investigated the anti-STAT3 mechanism of the dietary polyphenol, biochanin A (BCA), in IL-6-treated macrophages. METHODS: The effect of BCA on STAT3 and p38 MAPK was analyzed by immunoblot. The localization of both these transcription factors was determined by immunofluorescence and fractionation studies. The impact on DNA-binding activity of STAT3 was studied by luciferase assay. To understand which of the isoforms of p38 MAPK was responsible for BCA-mediated regulation of STAT3, overexpression of the proteins, site-directed mutagenesis, pull-down assays and computational analysis were performed. Finally, adhesion-migration assays and semi-quantitative PCR were employed to understand the biological effects of BCA-mediated regulation of STAT3. RESULTS: BCA prevented STAT3 phosphorylation (Tyr705) and increased p38 MAPK phosphorylation (Thr180/Tyr182) in IL-6-stimulated differentiated macrophages. This opposing modulatory effect of BCA was not observed in cells treated with other stress-inducing stimuli that activate p38 MAPK. BCA abrogated IL-6-induced nuclear translocation of phospho-STAT3 and its transcriptional activity, while increasing the cellular abundance of phospho-p38 MAPK. BCA-induced phosphorylation of p38δ, but not α, ß, or γ was responsible for impeding IL-6-induced STAT3 phosphorylation. Interestingly, interaction with phospho-p38δ masked the Tyr705 residue of STAT3, preventing its phosphorylation. BCA significantly reduced STAT3-dependent expression of icam-1 and mcp-1 diminishing IL-6-mediated monocyte adhesion and migration. CONCLUSION: This differential regulation of STAT3 and p38 MAPK in macrophages establishes a novel anti-inflammatory mechanism of BCA which could be important for the prevention of IL-6-associated chronic inflammatory diseases.

Impaired insulin exocytosis in chronic hepatitis C infection: contributory role of p38δ MAPK-protein kinase D-golgi complex axis.

Hepatitis C virus (HCV) infection and chronic hepatitis C (CHC) are associated with a measurable risk of insulin resistance (IR)/impaired glucose tolerance (IGT)/diabetes mellitus (DM). While loss of hepatic endocrine function contributes to liver cirrhosis in diabetic patients, onset and progression of IR/IGT to diabetes and exacerbation of incident hyperglycemia are ostensibly linked with chronic HCV infection. In this regard, the study by Chen J et al. appearing in Clinical Science (2020) (134(5) https://doi.org/10.1042/CS20190900) attempts to understand the mechanisms underlying the savaging effects of chronic HCV infection on insulin-producing pancreatic ß-cells and hence diabetic onset. The study investigated the role of mitogen-activated protein kinase (MAPK) p38δ-protein kinase D (PKD)-golgi complex axis in impacting insulin exocytosis. It was inferred that an insulin secretory defect of pancreatic ß-cells, owing to disrupted insulin exocytosis, to an extent explains ß-cell dysfunction in HCV-infected or CHC milieu. HCV infection negatively regulates first-phase and second-phase insulin secretion by impinging on PKD-dependent insulin secretory granule fission at trans-golgi network and insulin secretory vesicle membrane fusion events. This commentary highlights the study in question, that deciphered the contribution of p38δ MAPK-PKD-golgi complex axis to ß-cell dysfunction in CHC milieu. This pivotal axis proffers a formidable therapeutic opportunity for alleviation of double burden of glucose abnormalities/DM and CHC.

circTNFRSF21, a newly identified circular RNA promotes endometrial carcinoma pathogenesis through regulating miR-1227-MAPK13/ATF2 axis.

BACKGROUND: Circular RNA is a type of non-coding RNA with great potential in regulating gene expression and associated with disease progression. However, the role of circular RNA in endometrial carcinoma (EC) remains largely unknown. RESULTS: In this study, we found that circTNFRSF21 was highly expressed in EC cells and tumor tissues. In vitro and in vivo results showed that circTNFRSF21 was linked to increased EC cell growth and EC xenografts formation in nude mice. Mechanically, we showed that circTNFRSF21 acts as a sponge of miR-1227 in EC cells to rescue MAPK13/ATF2 signaling pathway activity. CONCLUSIONS: Our studies suggested that in the EC, circTNFRSF21 promotes EC formation through downregulating miR-1227 expression and activating MAPK13/ATF2 signaling pathway. These findings provide strong evidence that circTNFRSF21-miR-1227-MAPK13/ATF2 axis is a promising target for EC treatment. METHODS: qRT-PCR was used to detect circTNFRSF21expression in EC patients and EC cell lines. Cell growth, cell colony formation, cell apoptosis, cell cycle progression, and in vivo tumor formation assays were used to evaluate the roles of circTNFRSF21 in EC. Western blot, luciferase assay, RNA pull-down, siRNA knockdown, and CRISPR gene knock out assays were applied to study the mechanisms through which circTNFRSF21 regulates EC formation.

Chronic hepatitis C virus infection impairs insulin secretion by regulation of p38δ MAPK-dependent exocytosis in pancreatic ß-cells.

Chronic hepatitis C virus (HCV) infection has a close association with type 2 diabetes mellitus. Although the mechanisms of insulin resistance in chronic hepatitis C (CHC) patients have been extensively studied, little attention has been given to the role of ß-cell function in HCV-associated diabetes. Here, we analysed ß-cell function in CHC patients and HCV-infected mouse model and found in addition to insulin resistance, impaired pancreatic ß-cell function occurred in CHC patients and HCV-infected C/OTg mice, not only in diabetic individuals but also in individuals with impaired fasting glucose levels. Both first-phase and second-phase insulin secretion were impaired, at least partially due to the reduction of exocytosis of secretory insulin-containing granules following HCV infection. Up-regulated p38δ in HCV-infected ß-cells resulted in inactivation of protein kinase D (PKD), which was responsible for impaired insulin secretory capacity of ß-cells. Thus, impaired insulin secretion due to HCV infection in ß-cells contributes to HCV-associated type 2 diabetes. These findings provided a new inspiration for the important prognostic and therapeutic implications in the management of CHC patients with impaired fasting glucose.

Epigenome-wide analysis of common warts reveals aberrant promoter methylation.

Epigenetic alteration of host DNA is a common occurrence in both low- and high-risk human papillomavirus (HPV) infection. Although changes in promoter methylation have been widely studied in HPV-associated cancers, they have not been the subject of much investigation in HPV-induced warts, which are a temporary manifestation of HPV infection. The present study sought to examine the differences in promoter methylation between warts and normal skin. To achieve this, DNA was extracted from 24 paired wart and normal skin samples and inputted into the Infinium MethylationEPIC BeadChip microarray. Differential methylation analysis revealed a clear pattern of hyper- and hypomethylation in warts compared to normal skin, and the most differentially methylated promoters were found within the EIF3EP2, CYSLTR1, C10orf99, KRT6B, LAMA4, and H3F3B genes as well as the C9orf30 pseudogene. Moreover, pathway analysis showed that the H3F3A, CDKN1A, and MAPK13 genes were the most common regulators among the most differentially methylated promoters. Since the tissue samples were excised from active warts, however, this differential methylation could either be a cellular response to HPV infection or an HPV-driven process to establish the wart and/or promote disease progression. Conclusively, it is apparent that HPV infection alters the methylation status of certain genes to possibly initiate the formation of a wart and maintain its presence.

Approaching the challenges of MKK3/p38delta MAPK targeting for therapeutic purpose in colorectal cancer.

MKK3 is a member of the dual specificity kinase group specific upstream activator of p38 MAPK proteins. We originally identified MKK3 as mutant p53 (mutp53) gain-of-function (GOF) upregulated target gene in different tumor models. To deeply investigate the MKK3 functions in cancer, taking advantage of a panel of authenticated colorectal cancer (CRC) lines and primary colonocytes, we found that MKK3 activates specifically p38delta MAPK protein, which signaling is further triggered by 5-fluorouracil (5-FU) treatments, a largely adopted chemotherapeutic drug in CRC clinical practice. The overall achieved results proposed the MKK3/p38delta MAPK as relevant molecular axis involved in abrogating efficacy to 5-FU treatments in CRC. This commentary will provide an overall discussion of the results that have been achieved contextualizing them in the overview of the knowledge in the p38 MAPK field in cancer disease.

MKK3 sustains cell proliferation and survival through p38DELTA MAPK activation in colorectal cancer.

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide and understanding its underlying molecular mechanisms is crucial for the development of therapeutic strategies. The mitogen-activated protein kinase-kinase 3 (MKK3) is a specific activator of p38 MAP kinases (p38 MAPKs), which contributes to the regulation of several cellular functions, such as proliferation, differentiation, apoptosis as well as response to drugs. At present, the exact MKK3/p38 MAPK pathway contribution in cancer is heavily debated because of its pleiotropic function. In this work, we retrospectively explored the prognostic and pathobiologic relevance of MKK3 in a cohort of CRC patients and assessed MKK3 molecular functions in a panel of CRC lines and colonocytes primary cultures. We found increased MKK3 levels in late-stage CRC patients which correlated with shorter overall survival. Herein, we report that the MKK3 targeting by inducible RNA interference univocally exerts antitumor effects in CRC lines but not in primary colonocytes. While MKK3 depletion per se affects growth and survival by induction of sustained autophagy and death in some CRC lines, it potentiates response to chemotherapeutic drug 5-fluorouracil (5-FU) in all of the tested CRC lines in vitro. Here, we demonstrate for the first time that in CRC the MKK3 specifically activates p38delta MAPK isoform to sustain prosurvival signaling and that such effect is exacerbated upon 5-FU challenge. Indeed, p38delta MAPK silencing recapitulates MKK3 depletion effects in CRC cells in vitro and in vivo. Overall, our data identified a molecular mechanism through which MKK3 supports proliferation and survival signaling in CRC, further supporting MKK3 as a novel and extremely attractive therapeutic target for the development of promising strategies for the management of CRC patients.