LY6G6D is Epigenetically Activated in Classical Colorectal Adenocarcinoma and Hyper-Methylated in Mucinous Subtypes Determining Resistance to FOLFOX Therapeutic Regimens.

Background: Colorectal cancer (CRC) represents a significant and ever-increasing societal threat and burden. Activation of Lymphocyte antigen 6G6D could induce anti-tumor specific immunity unique to CRC, but factors regulating its activation remain obscure.Methods: Transcriptome, epigenome and proteomic data from TCGA and independent database were investigated using in silico approaches. Expression of candidate genes was independently validated by immunohistochemistry in CRC tissues. In vitro RNA mediated gene silencing of putative regulators, treatment with MEK and p38 MAPK inhibitors and Bioinformatic prediction were carried out to unveil LY6G6D regulation.Results: LY6G6D is down-regulated in mucinous CRC regardless its anatomic location, while its activation progresses through the classical adenoma-carcinoma sequence. The lack of LY6G6D expression in mucinous CRC involves alterations of secretome-based immune responses. DNA methylation changes in LY6G6D promoter are intimately related to its transcript regulation, epigenomic and different histological subtypes. RNA-mediated gene silencing and chemical inhibition of p38α MAPK as well as DNA methyltransferase DNMT1 knock-down lead to a decrease in LY6G6D expression, supporting that p38a MAPK and DNA methylases mediated LY6G6D regulation. Cancer cells with an intact p38α MAPK stabilize LY6G6D expression allowing effective responses to trametinib, a MEK inhibitor able to exert anti-inflammatory effects. In a metastatic CRC subset, LY6G6D hypermethylation predicts resistance to FOLFOX first-line therapy, supporting the idea that its cancer-specific hypomethylation and consequent activation may be a tissue-specific mechanism of anti-tumor immunity. Conclusions: LY6G6D has the potentiality to be used as a biomarker for patient stratification and immune therapeutic intervention of mucinous versus non-mucinous CRC.

P38α Deficiency in Macrophages Ameliorates Murine Experimental Colitis by Regulating Inflammation and Immune Process

Introduction: P38α is a mitogen-activated protein kinase (MAPK) that mediates inflammatory responses. P38α alterations have been associated with the inflammation-related diseases. However, the role of macrophages-derived p38α in dextran sulfate sodium (DSS)-induced murine experimental colitis remains unclear.Objectives: We characterized the role of macrophages-derived p38α in DSS-induced colitis.Methods: The expression of macrophage-derived p38α in human colitis and normal tissues was measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) analysis. Macrophage-specific p38α knockout (p38αΔMφ) and wild type (WT) mice administrated by 3% DSS were used to establish experimental colitis. The alterations in inflammatory cytokines, intestinal epithelial barrier, cell proliferation and cell apoptosis between p38αΔMφ and WT groups were determined by IHC, immunofluorescence (IF), TdT-mediated dUTP Nick-End Labeling (TUNEL) and Western blot analyses. The enriched pathways between p38αΔMφ and WT groups were identified by RNA-seq and KEGG analysis. SB203580 and BIRB796 as the p38 MAPK inhibitors were used to treat DSS-induced colitis. Results: p38α was co-localized with CD68 in the cytoplasm and their co-expression indicated an increased level in colitis tissues as compared with the normal tissues. P38α deficiency in macrophages was sufficient to suppress the exacerbated clinical symptoms and inflammation responses in experimental colitis, followed by reducing cytokine release, increasing MUC-2 and Claudin-2 secretion and promoting colonic mucosa repair. Further investigations validated that the immune process-related factors such as Lgals9, Rtp4, Ddx60, Nlrp1b, Hsh2d, Oas2 and Oas3 were upregulated in colon tissues from p38αΔMφ group as compared with the WT group. Inhibition of p38 MAPK attenuated DSS-induced colitis. Conclusion: Our findings demonstrated that p38α deficiency in macrophages ameliorated murine experimental colitis by regulating inflammation and immune process.

P38α Deficiency in Macrophages Ameliorates Murine Experimental Colitis by Regulating Inflammation and Immune Process

Introduction: P38α is a mitogen-activated protein kinase (MAPK) that mediates inflammatory responses. P38α alterations have been associated with the inflammation-related diseases. However, the role of macrophages-derived p38α in dextran sulfate sodium (DSS)-induced murine experimental colitis remains unclear.Objectives: We characterized the role of macrophages-derived p38α in DSS-induced colitis.Methods: The expression of macrophage-derived p38α in human colitis and normal tissues was measured by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) analysis. Macrophage-specific p38α knockout (p38αΔMφ) and wild type (WT) mice administrated by 3% DSS were used to establish experimental colitis. The alterations in inflammatory cytokines, intestinal epithelial barrier, cell proliferation and cell apoptosis between p38αΔMφ and WT groups were determined by IHC, immunofluorescence (IF), TdT-mediated dUTP Nick-End Labeling (TUNEL) and Western blot analyses. The enriched pathways between p38αΔMφ and WT groups were identified by RNA-seq and KEGG analysis. SB203580 and BIRB796 as the p38 MAPK inhibitors were used to treat DSS-induced colitis. Results: p38α was co-localized with CD68 in the cytoplasm and their co-expression indicated an increased level in colitis tissues as compared with the normal tissues. P38α deficiency in macrophages was sufficient to suppress the exacerbated clinical symptoms and inflammation responses in experimental colitis, followed by reducing cytokine release, increasing MUC-2 and Claudin-2 secretion and promoting colonic mucosa repair. Further investigations validated that the immune process-related factors such as Lgals9, Rtp4, Ddx60, Nlrp1b, Hsh2d, Oas2 and Oas3 were upregulated in colon tissues from p38αΔMφ group as compared with the WT group. Inhibition of p38 MAPK attenuated DSS-induced colitis. Conclusion: Our findings demonstrated that p38α deficiency in macrophages ameliorated murine experimental colitis by regulating inflammation and immune process.

Synthesis and Biological Evaluation of 2,3,4-Triaryl-1,2,4-oxadiazol-5-ones as p38 MAPK Inhibitors

A series of azastilbene derivatives, characterized by the presence of the 1,2,4-oxadiazole-5-one system as a linker of the two aromatic rings of stilbenes, have been prepared as novel potential inhibitors of p38 MAPK. Biological assays indicated that some of the synthesized compounds are endowed with good inhibitory activity towards the kinase. Molecular modeling data support the biological results showing that the designed compounds possess a reasonable binding mode in the ATP binding pocket of p38α kinase with a good binding affinity.

Is p38 MAPK Associated to Drugs of Abuse-Induced Abnormal Behaviors?

The family members of the mitogen-activated protein kinases (MAPK) mediate a wide variety of cellular behaviors in response to extracellular stimuli. p38 MAPKs are key signaling molecules in cellular responses to external stresses and regulation of pro-inflammatory cytokines. Some studies have suggested that p38 MAPK in the region of the nucleus accumbens is involved in abnormal behavioral responses induced by drugs of abuse. In this review, we discuss the role of the p38 MAPK in the rewarding effects of drugs of abuse. We also summarize the implication of p38 MAPK in stress, anxiety, and depression. We opine that p38 MAPK activation is more closely associated to stress-induced aversive responses rather than drug effects per se, in particular cocaine. p38 MAPK is only involved in cocaine reward, predominantly when promoted by stress. Downstream substrates of p38 that may contribute to the p38 MAPK associated-behavioral responses are proposed. Finally, we suggest p38 MAPK inhibitors as possible therapeutic interventions against stress-related disorders by potentially increasing resilience against stress and addiction relapse induced by adverse experiences.

The Expanding Role of p38 Mitogen-Activated Protein Kinase in Programmed Host Cell Death

The p38 mitogen-activated protein kinase (MAPK) is involved in a multitude of essential cellular processes. The kinase is activated in response to environmental stresses, including bacterial infections and inflammation, to regulate the immune response of the host. However, recent studies have demonstrated that pathogens can manipulate p38 MAPK signaling for their own benefit to either prevent or induce host cell apoptosis. In addition, there is evidence demonstrating that p38 MAPK is a potent trigger of pathogen-induced necrosis driven by mitochondrial membrane disruption. Given the large number of p38 MAPK inhibitors that have been tested in clinical trials, these findings provide an opportunity to repurpose these drugs for improved control of infectious diseases.

p38α MAPK signaling drives pharmacologically reversible brain and gastrointestinal phenotypes in the SERT Ala56 mouse

Autism spectrum disorder (ASD) is a common neurobehavioral disorder with limited treatment options. Activation of p38 MAPK signaling networks has been identified in ASD, and p38 MAPK signaling elevates serotonin (5-HT) transporter (SERT) activity, effects mimicked by multiple, hyperfunctional SERT coding variants identified in ASD subjects. Mice expressing the most common of these variants (SERT Ala56) exhibit hyperserotonemia, a biomarker observed in ASD subjects, as well as p38 MAPK-dependent SERT hyperphosphorylation, elevated hippocampal 5-HT clearance, hypersensitivity of CNS 5-HT1A and 5-HT2A/2C receptors, and behavioral and gastrointestinal perturbations reminiscent of ASD. As the α-isoform of p38 MAPK drives SERT activation, we tested the hypothesis that CNS-penetrant, α-isoform–specific p38 MAPK inhibitors might normalize SERT Ala56 phenotypes. Strikingly, 1-week treatment of adult SERT Ala56 mice with MW150, a selective p38α MAPK inhibitor, normalized hippocampal 5-HT clearance, CNS 5-HT1A and 5-HT2A/2C receptor sensitivities, social interactions, and colonic motility. Conditional elimination of p38α MAPK in 5-HT neurons of SERT Ala56 mice restored 5-HT1A and 5-HT2A/2C receptor sensitivities as well as social interactions, mirroring effects of MW150. Our findings support ongoing p38α MAPK activity as an important determinant of the physiological and behavioral perturbations of SERT Ala56 mice and, more broadly, supports consideration of p38α MAPK inhibition as a potential treatment for core and comorbid phenotypes present in ASD subjects.

A post-transcriptional program of chemoresistance by AU-rich elements and TTP

BackgroundQuiescence (G0) is a transient, cell cycle-arrested state. By entering G0, cancer cells survive unfavorable conditions such as chemotherapy and cause relapse. While G0 cells have been studied at the transcriptome level, how post-transcriptional regulation contributes to their chemoresistance remains unknown.ResultsWe induced chemoresistant and quiescent (G0) leukemic cells by serum-starvation or chemotherapy treatment. To study post-transcriptional regulation in G0 leukemic cells, we systematically analyzed their transcriptome, translatome, and proteome. We find that our resistant G0 cells recapitulate gene expression profiles of in vivo chemoresistant leukemic and G0 models. In G0 cells, canonical translation initiation is inhibited; yet we find that inflammatory genes are highly translated, indicating alternative post-transcriptional regulation. Importantly, AU-rich elements (AREs) are significantly enriched in the up-regulated G0 translatome and transcriptome. Mechanistically, we find the stress-responsive p38 MAPK-MK2 signaling pathway stabilizes ARE mRNAs by phosphorylation and inactivation of mRNA decay factor, tristetraprolin (TTP) in G0. This permits expression of ARE-bearing TNFα and DUSP1 that promote chemoresistance. Conversely, inhibition of TTP phophorylation by p38 MAPK inhibitors and non-phosphorylatable TTP mutant decreases ARE mRNAs and sensitizes leukemic cells to chemotherapy. Furthermore, co-inhibiting p38 MAPK and TNFα—prior to or along with chemotherapy—substantially reduced chemoresistance in primary leukemic cells ex vivo and in vivo.ConclusionsThese studies uncover post-transcriptional regulation underlying chemoresistance in leukemia. Our data reveal the p38 MAPK-MK2-TTP axis as a key regulator of expression of ARE bearing mRNAs that promote chemoresistance. By disrupting this pathway, we developed an effective combination therapy against chemosurvival.