Signal-regulated Kinase Signaling Pathway Research Articles

Utility of patient-derived xenografts to evaluate drug sensitivity and select optimal treatments for individual non-small-cell lung cancer patients.

Patient-derived xenograft (PDX) is currently considered a preferred preclinical model to evaluate drug sensitivity, explore drug resistance mechanisms, and select individualized treatment regimens. Histopathological examination, immunohistochemistry and whole-exome sequencing confirmed similarity between our PDX tumors and primary tumors in terms of morphology and genetic characteristics. The drug reactivity of the PDX tumor was validated in vivo. The mechanisms of acquired resistance to Osimertinib PDX tumors were investigated by WES and WB. We successfully established 13 NSCLC-PDXs derived from 62 patients, including eight adenocarcinomas, four squamous-cell carcinoma, and one large-cell neuroendocrine carcinoma. Histological subtype and clinical stage were significant factors affecting the successful PDXs establishment. The treatment responses to conventional chemotherapy in PDXs were entirely consistent with that of their corresponding patients. According to the genetic status of tumors, more appropriate targeted agents were selected in PDXs for their corresponding patients as alternative treatment options. In addition, a PDX model with acquired resistance to osimertinib was induced, and the overactivation of RAS mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) signaling pathway caused by the dual-specificity phosphatase 6 (DUSP6) M62I mutation was found to play a key role in the development of osimertinib resistance. Trametinib, a specific inhibitor of the MAPK-ERK pathway significantly slowed down the tumor growth in osimertinib-resistant PDX models, providing an alternative treatment in patients after osimertinib failure.

Differential Effects of Extracellular Vesicles from Two Different Glioblastomas on Normal Human Brain Cells

Background/Objectives: Glioblastomas (GBMs) are dreadful brain tumors with abysmal survival outcomes. GBM extracellular vesicles (EVs) dramatically affect normal brain cells (largely astrocytes) constituting the tumor microenvironment (TME). We asked if EVs from different GBM patient-derived spheroid lines would differentially alter recipient brain cell phenotypes. This turned out to be the case, with the net outcome of treatment with GBM EVs nonetheless converging on increased tumorigenicity. Methods: GBM spheroids and brain slices were derived from neurosurgical patient tissues following informed consent. Astrocytes were commercially obtained. EVs were isolated from conditioned culture media by ultrafiltration, concentration, and ultracentrifugation. EVs were characterized by nanoparticle tracking analysis, electron microscopy, biochemical markers, and proteomics. Astrocytes/brain tissues were treated with GBM EVs before downstream analyses. Results: EVs from different GBMs induced brain cells to alter secretomes with pro-inflammatory or TME-modifying (proteolytic) effects. Astrocyte responses ranged from anti-viral gene/protein expression and cytokine release to altered extracellular signal-regulated protein kinase (ERK1/2) signaling pathways, and conditioned media from EV-treated cells increased GBM cell proliferation. Conclusions: Astrocytes/brain slices treated with different GBM EVs underwent non-identical changes in various omics readouts and other assays, indicating “personalized” tumor-specific GBM EV effects on the TME. This raises concern regarding reliance on “model” systems as a sole basis for translational direction. Nonetheless, net downstream impacts from differential cellular and TME effects still led to increased tumorigenic capacities for the different GBMs.

ARL8B promotes hepatocellular carcinoma progression and inhibits antitumor activity of lenvatinib via MAPK/ERK signaling by interacting with RAB2A

Tumor recurrence and metastasis are important factors affecting postoperative survival in hepatocellular carcinoma (HCC) patients. ADP Ribosylation factor-like GTPase 8B (ARL8B) plays a crucial role in many biological processes, including lysosomal function, immune response, and cellular communication, all of which are related to the occurrence and development of tumors. However, its role in HCC remains unclear. Herein, we revealed that ARL8B is consistently elevated in HCC tissues compared to normal liver tissues, suggesting an unfavorable outcome in HCC patients. Increased ARL8B levels promoted the malignant phenotype of HCC in vitro and in vivo. Notably, ARL8B also induced epithelial-to-mesenchymal transition (EMT) in HCC cells. Mechanistically, the results of bioinformatics analysis combined with mass spectrometry revealed the potential downstream target molecule RAB2A of ARL8B. ARL8B directly interacted with RAB2A and increased the levels of GTP-bound RAB2A, thereby contributing to the activation of the extracellular signal-regulated kinase (ERK) signaling pathway. Interestingly, knockout of ARL8B in Hep3B cells enhanced the antitumor activity of lenvatinib in vitro and in vivo. Furthermore, AAV-shARL8B enhanced the inhibition of HCC growth through lenvatinib, providing new insights into its mechanism of action in lenvatinib-insensitive patients. In conclusion, ARL8B promotes the malignant phenotype of HCC and EMT via RAB2A mediated activation of the MAPK/ERK signaling pathway and is expected to be a valuable prognostic indicator and therapeutic target for HCC patients.

Effects of Proteasome 20S Subunit Beta 8 on Proliferation,Migration,and Invasion of Clear Cell Renal Cell Carcinoma Cells via Mitogen-Activated Protein Kinase Kinase/Extracellular Signal-Regulated Kinase Signaling Pathway

Objective To explore the effects of proteasome 20S subunit beta 8 (PSMB8) on the proliferation,migration,and invasion of clear cell renal cell carcinoma (ccRCC) cells and whether PSMB8 promotes tumor progression by activating the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway. Methods The Cancer Genome Atlas was employed to analyze the mRNA levels of PSMB8 in ccRCC and normal tissue,and the expression levels of PSMB8 in ccRCC tissue and cells were determined by real-time quantitative PCR,Western blotting,and immunohistochemistry.Furthermore,the cell lines with stable overexpression and knockdown of PSMB8 were constructed.The CCK-8 assay and colony formation assay were employed to examine the cell proliferation,and the wound healing assay and Transwell assay were employed to examine the invasion and migration of cells.Kyoto Encyclopedia of Genes and Genomes pathway enrichment was performed to analyze the co-expressed genes of PSMB8.Western blotting was used to measure the phosphorylation levels of the proteins in the MEK/ERK signaling pathway.Finally,the rescue experiment was carried out with the ERK agonist C16-PAF. Results Compared with the normal tissue,the ccRCC tissue showed up-regulated mRNA and protein levels of PSMB8 (both P<0.001),which were associated with the TNM stage of patients with ccRCC (P<0.001).Compared with the negative control group,overexpression of PSMB8 promoted the proliferation (P=0.021,P=0.039),migration and invasion (all P<0.001) of 786-O and ACHN cells,and the knockdown of PSMB8 inhibited the proliferation (P=0.022,P=0.005),migration and invasion (all P<0.001) of 786-O and ACHN cells.The pathway enrichment analysis of co-expressed genes of PSMB8 predicted the mitogen-activated protein kinase signaling pathway (P<0.001).After the knockdown of PSMB8,786-O and ACHN cells showed lowered phosphorylation levels of MEK1/2 (P=0.017,P=0.016) and ERK1/2 (P=0.010,P=0.040) and down-regulated transcription levels of ERK downstream factors c-Myc (P=0.043,P=0.038),c-Fos (P=0.025,P=0.008),and CyclinD1 (P=0.006,P=0.047).Compared with the ERK agonist C16-PAF group,the PSMB8 knockdown + C16-PAF group showed inhibited proliferation (P=0.003,P=0.002),migration and invasion (all P<0.001) of 786-O and ACHN cells. Conclusion PSMB8 may promote the proliferation,migration,and invasion of ccRCC cells by activating the MEK/ERK signaling pathway.

FUT6 Suppresses the Proliferation, Migration, Invasion, and Epithelial-Mesenchymal Transition of Esophageal Carcinoma Cells via the Epidermal Growth Factor Receptor/Extracellular Signal-Regulated Kinase Signaling Pathway.

Esophageal cancer (ESCA) is a high-incidence disease worldwide, of which the 5-year survival rate remains dismal since the cellular basis of ESCA remains largely unclear. Herein, we attempted to examine the manifestation of fucosyltransferase-6 (FUT6) in ESCA and the associated mechanisms. The GSE161533 dataset was used to analyze a crucial gene in ESCA. The expression of FUT6 was investigated in normal esophageal epithelial cells and ESCA cell lines. Following FUT6 knockdown or overexpression, cell proliferation, migration, invasion, and levels of epithelial–mesenchymal transition (EMT)-related and epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) signaling pathway-related proteins were evaluated using CCK-8, Transwell, and Western blotting with antibodies against EGFR, p-EGFR, E-cadherin, Vimentin, N-cadherin, ERK1/2, and p-ERK1/2), respectively. EGF was administered to stimulate the EGFR/ERK signaling pathway, followed by the assessment of cellular activity. Database analysis revealed that FUT6 was downregulated in the ESCA cells. Our study indicated that FUT6 is suppressed in various ESCA cell lines. Moreover, cell proliferation, invasion, migration, and EMT-related protein levels were conspicuously enhanced or restrained by FUT6 disruption or overexpression. FUT6 overexpression suppressed the malignant activities of the cells when stimulated by EGF, including inhibition of cell growth, movement, invasion, and EMT advancement, as well the reduction the levels of EGFR/ERK pathway proteins. In conclusion, FUT6 can suppress the EGFR/ERK signaling pathway activated by EGF, leading to the potential attenuation of ESCA cell proliferation, invasion, migration, and EMT.

Jaranol Loaded in Ferroferric Oxide Nanoparticles Inhibits the Activities of Liver Cancer Cell Through Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Signaling Pathway

Liver cancer is highly aggressive and the MEK/ERK signaling regulates tumor cell proliferation and metastasis. Jaranol is a natural product with anti-proliferative and anti-metastatic effects in several tumors. However, its interaction with the MEK/ERK pathway in liver cancer is unclear. This study explores whether ferroferric oxide nanoparticles-loaded Jaranol inhibits proliferation and metastasis in liver cancer cell Hep3B by regulating MEK/ERK signaling, and its underlying mechanism. Fe3O4-Jaranol nanoparticles were prepared and used in Hep3B experiments to observe the biological efficacy of Fe3O4-Jaranol, and further explore its effect and mechanism on the MEK/ERK pathway using PCR, WB, etc. Fe3O4-Jaranol were successfully prepared with a certain tumor suppressor effect in liver cancer. The expression of MEK/ERK was increased in liver cancer. Inhibiting its pathway activity suppressed the development of liver cancer. Trametinib and C16-PAF were used to inhibit Hep3B respectively. MEK expression in cells treated with Trametinib was reduced accompanied by a low expression of ERK, while the expression of MEK and ERK levels in the C16-PAF group showed an opposite trend, indicating that Trametinib, C16-PAF successfully intervened on MEK and ERK. Further analysis of the activity of Hep3B cells found that the proliferation ability of the Trametinib group was significantly inhibited. Fe3O4-Jaranol significantly inhibited liver cancer cell Hep3B and this effect was accomplished by inhibiting MEK/ERK signaling, causing tumor cell proliferation to be restricted and reducing the ability to metastasize. This research result provides strong evidence for a deep understanding of the mechanism of Jaranol in treating liver cancer, so as to better guide clinical practice.

Neural Development and Repair Induced by Femtosecond Laser Stimulation.

Dendritic spines function as postsynaptic sites, receiving excitatory signals from presynaptic axons. The synaptic plasticity of spines underlies the refinement of neuronal circuits. Neural cognitive disorders are commonly associated with the impairment and elimination of dendritic spines. In this study, we report an all-optical method to activate dendritic spine growth and regeneration by a single short flash of femtosecond laser stimulation. The inhibited development and loss of spines can be rescued by a transient illumination of the laser inside a micrometer region of the soma by activating the extracellular signal-regulated kinase (ERK) signaling pathway. The rescued neurons exhibit function. Hence we provide a potential noninvasive method for the regeneration of dendritic spines.

Decoding the Genetic Threads of Disc Degeneration

Abstract Degenerative disc disease (DDD) is a prevalent musculoskeletal disorder characterized by the progressive degeneration of intervertebral discs, often leading to chronic low back pain and disability. While the etiology of DDD is multifactorial, genetic factors play a significant role in disease susceptibility and progression. This review provides a comprehensive overview of the genetic aspects of DDD, summarizing previously reported genes and variations associated with the disease. Through an analysis of animal studies and molecular pathways implicated in disc degeneration, including the lipid kinase phoshoinositide-3-kinase signaling pathway (PI3K-Akt), mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway (MAPK-ERK), Wingless-related integration (Wnt)/β-catenin, Sonic Hedgehog (Shh), and mammalian target of rapamycin (mTOR) pathways, this review elucidates the intricate interplay between genetic factors and disc pathology. Several candidate genes have been identified in association with DDD, including those involved in extracellular matrix regulation, inflammation, and cell signaling. Genome-wide association studies have further expanded our understanding of the genetic architecture underlying DDD, revealing novel susceptibility loci and pathways. Animal studies utilizing genetically modified models have provided valuable insights into the molecular mechanisms driving disc degeneration and have validated the relevance of specific genetic pathways in disease pathogenesis. Understanding the genetic basis of DDD holds promise for identifying individuals at risk, developing predictive biomarkers, and informing personalized treatment approaches. Furthermore, elucidating the molecular pathways involved in disc degeneration may lead to the identification of novel therapeutic targets for DDD management. Overall, this review consolidates current knowledge on DDD genetics and pathways, providing a foundation for future research endeavors aimed at unraveling the intricate genetic mechanisms underlying this prevalent musculoskeletal disorder.

MAPK signaling pathway participates in the regulation of intestinal phosphorus and calcium absorption in broiler chickens via 1,25-dihydroxyvitamin D3

Four experiments were performed to investigate the role of the mitogen-activated protein kinase (MAPK) signaling pathway in intestinal absorption of phosphorus (P) and calcium (Ca) in broiler chickens. Experiment 1 assessed how dietary levels of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) influence the gene expression of intestinal P and Ca transporters in broilers. Experiment 2 evaluated the effects of 1,25(OH)2D3 administered via intraperitoneal injection on the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK) signaling pathways. Experiments 3 and 4 investigated the effect of ERK and p38MAPK inhibitors on the expression of intestinal P and Ca transporters. The findings demonstrated that broilers (1-21 days old) fed a 1,25(OH)2D3-deficient diet (0.625 µg/kg) exhibited reduced body weight, tibia P and Ca levels, and mRNA levels of P transporters (NaPi-IIb, PiT-1, and PiT-2), Ca transporters (NCX1, PMCA1b, and CaBP-D28k), vitamin D receptors (VDR), ERK, and p38MAPK in the duodenum (Experiment 1) (P < 0.05). By comparison, the growth, bone quality, and mRNA levels of genes (except for duodenal NaPi-IIb) in broilers were similar to those in broilers fed the control diet when dietary 1,25(OH)2D3 was adequate (5 µg/kg) (Experiment 1) (P > 0.05). After intraperitoneal injection of 1,25(OH)2D3, the mRNA level of jejunal NaPi-IIb and the protein level of p-p38MAPK/t-p38MAPK in broilers (9-14 days old) decreased (P < 0.05), whereas the mRNA level of CaBP-D28k and the protein level of p-ERK/t-ERK increased (Experiment 2) (P < 0.05). The mRNA and protein expression of jejunal NaPi-IIb and the protein expression of CaBP-D28k in broilers (9-17 days old) treated with the ERK inhibitor PD98059 were greater than those in the control group (Experiment 3) (P < 0.05). Similarly, compared with control broilers, broilers (9-17 days old) treated with the p38MAPK inhibitor SB203580 showed elevated mRNA expression of jejunal NaPi-IIb and CaBP-D28k (Experiment 4) (P < 0.05). These results suggest that adequate supplementation with 1,25(OH)2D3 (5 µg/kg) can restore broiler growth and bone quality by upregulating the transcription of genes involved in intestinal P and Ca absorption. Additionally, the ERK and p38MAPK signaling pathways are implicated in the modulatory effect of 1,25(OH)2D3 on the absorption of P and Ca in broilers.

Electrical Stimulations Generated by P(VDF-TrFE) Films Enhance Adhesion Forces and Odontogenic Differentiation of Dental Pulp Stem Cells (DPSCs).

Biophysical and biochemical cues of biomaterials can regulate cell behaviors. Dental pulp stem cells (DPSCs) in pulp tissues can differentiate to odontoblast-like cells and secrete reparative dentin to form a barrier to protect the underlying pulp tissues and enable complete pulp healing. Promotion of the odontogenic differentiation of DPSCs is essential for dentin regeneration. The effects of the surface potentials of biomaterials on the adhesion and odontogenic differentiation of DPSCs remain unclear. Here, poly(vinylidene fluoride-trifluoro ethylene) (P(VDF-TrFE)) films with different surface potentials were prepared by the spin-coating technique and the contact poling method. The cytoskeletal organization of DPSCs grown on P(VDF-TrFE) films was studied by immunofluorescence staining. Using atomic force microscopy (AFM), the lateral detachment forces of DPSCs from P(VDF-TrFE) films were quantified. The effects of electrical stimulation generated from P(VDF-TrFE) films on odontogenic differentiation of DPSCs were evaluated in vitro and in vivo. The unpolarized, positively polarized, and negatively polarized films had surface potentials of -52.9, +902.4, and -502.2 mV, respectively. DPSCs on both negatively and positively polarized P(VDF-TrFE) films had larger cell areas and length-to-width ratios than those on the unpolarized films (P < 0.05). During the detachment of DPSCs from P(VDF-TrFE) films, the average magnitudes of the maximum detachment forces were 29.4, 72.1, and 53.9 nN for unpolarized, positively polarized, and negatively polarized groups, respectively (P < 0.05). The polarized films enhanced the mineralization activities and increased the expression levels of the odontogenic-related proteins of DPSCs compared to the unpolarized films (P < 0.05). The extracellular signal-regulated kinase (ERK) signaling pathway was involved in the odontogenic differentiation of DPSCs as induced by surface charge. In vivo, the polarized P(VDF-TrFE) films enhanced adhesion of DPSCs and promoted the odontogenic differentiation of DPSCs by electrical stimulation, demonstrating a potential application of electroactive biomaterials for reparative dentin formation in direct pulp capping.

Downregulation of KLF5 by EBER1 via the ERK signaling pathway in EBV-positive nasopharyngeal carcinoma cells: implications for latent EBV infection.

Nasopharyngeal carcinoma (NPC) carcinogenesis and malignant transformation are intimately associated with Epstein-Barr virus (EBV) infection. A zinc-fingered transcription factor known as Krüppel-like factor 5 (KLF5) has been shown to be aberrantly expressed in a number of cancer types. However, little is known about the regulatory pathways and roles of KLF5 in EBV-positive NPC. Our study found that KLF5 expression was significantly lower in EBV-positive NPC than in EBV-negative NPC. Further investigation revealed that EBER1, which is encoded by EBV, down-regulates KLF5 via the extracellular signal-regulated kinase (ERK) signalling pathway. This down-regulation of KLF5 by EBER1 contributes to maintaining latent EBV infection in NPC. Furthermore, we uncovered the biological roles of KLF5 in NPC cells. Specifically, KLF5 may influence the cell cycle, prevent apoptosis, and encourage cell migration and proliferation - all of which have a generally pro-cancer impact. In conclusion, these findings offer novel strategies for EBV-positive NPC patients' antitumour treatment.

Abstract 1677: The emerging role of the Plasminogen-Apple-Nematode (PAN) domain in cancer therapy

Abstract The Plasminogen-Apple-Nematode (PAN) domain, with a core of four to six cysteine residues, is found in more than 28,000 proteins across 959 genera. However, its role in protein function still needs to be elucidated. Numerous proteins initially characterized the PAN domain, including a well-known master regulator for cancer cell proliferation, HGF (Hepatocyte growth factor). Abnormal regulation of HGF-mediated signaling results in multiple deadly cancers. The binding of HGF to its cell surface receptor, c-MET, triggers signaling pathways, which leads to cancer. Here, we show that mutating four core cysteine residues in the HGF PAN domain reduces c-MET interaction, subsequent c-MET autophosphorylation, and phosphorylation of its downstream targets, perinuclear localization, cellular internalization of HGF and its receptor, c-MET, and c-MET ubiquitination. Furthermore, transcriptional activation of HGF/c-MET signaling-related genes involved in cancer progression, invasion, metastasis, and cell survival was impaired. Thus, targeting the PAN domain of HGF may represent a mechanism for selectively regulating the binding and activation of the c-MET pathway. Additionally, we found this domain in the tumor suppressor gene, MST1 (macrophage stimulating 1), and mutating the domain altered the protein function through protein stability and ubiquitination. In another study, we show that cysteine residues in the vestigial plasminogen-apple-nematode (PAN) domain of NRP1 are necessary for SARS-CoV-2 spike protein internalization. Mutating novel cysteine residues in the PAN altered NRP1 stability and downstream activation of the extracellular signal-regulated kinase (ERK) signaling pathway, impairing its interaction with the spike protein. These results show the diverse critical role of the PAN domain beyond cancer therapy. Citation Format: Kuntal De, Debjani Pal, Wellington Muchero. The emerging role of the Plasminogen-Apple-Nematode (PAN) domain in cancer therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1677.

PI3K/Akt/Erk signaling pathway mediates neuroprotection of CaMKⅡγ and CaMKⅡδ against ischemic reperfusion injury in mice

To observe neuroprotective effects of Ca2+/calmodulin-dependent kinase Ⅱ (CaMK Ⅱ)γ and CaMkII δ against acute neuronal ischemic reperfusion injury in mice and explore the underlying mechanism. Primary cultures of brain neurons isolated from fetal mice (gestational age of 18 days) were transfected with two specific siRNAs (si-CAMK2G and si-CAMK2D) or a control sequence (si-NT). After the transfection, the cells were exposed to oxygen-glucose deprivation/reperfusion (OGD/R) conditions for 1 h followed by routine culture. The expressions of phosphatidylinositol-3-kinase/extracellular signal-regulated kinase (PI3K/Akt/Erk) signaling pathway components in the neurons were detected using immunoblotting. The expressions of the PI3K/Akt/Erk signaling pathway proteins were also detected in the brain tissues of mice receiving middle cerebral artery occlusion (MCAO) or sham operation. The neuronal cells transfected with siCAMK2G showed significantly lower survival rates than those with si-NT transfection at 12, 24, 48, and 72 h after OGD/R (P < 0.01), and si-CAMK2G transfection inhibited OGD/R-induced upregulation of CaMKⅡγ expression. Compared to si-NT, transfection with si-CAMK2G and si-CAMK2D both significantly inhibited the expressions of PI3K/Akt/Erk signaling pathway components (P < 0.01). In the mouse models of MCAO, the expressions of CaMKⅡδ and CaMKⅡγ were significantly increased in the brain, where activation of the PI3K/Akt/Erk signaling pathway was detected. The expression levels of CaMKⅡδ, CaMKⅡγ, Erk, phosphorylated Erk, Akt, and phosphorylated Akt were all significantly higher in MCAO mice than in the sham-operated mice at 24, 48, 72, and 96 h after reperfusion (P < 0.05). The neuroprotective effects of CaMKⅡδ and CaMKⅡγ against acute neuronal ischemic reperfusion injury are mediated probably by the PI3K/Akt/Erk pathway.

Design, synthesis and evaluation of the first DYRK1A degrader for promoting the proliferation of pancreatic β-cells

Dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) is the most promising target for diabetes treatment by promoting β-cell proliferation. The desmethylbellidifolin (DMB) as a DYRK1A inhibitor could facilitate β-cell proliferation in vivo and in vitro. However, DMB has the problem of weak binding affinity to DYRK1A, which means that continuous high concentration administration of DMB is effective for the diabetes. In order to solve this problem, we designed and synthesized a series of DMB-based proteolysis targeting chimeras (PROTACs) by taking advantage of the property of PROTAC that induce protein degradation in a cycle-catalytic manner. MDM2-based PROTAC X1–4P-MDM2 was identified as the most active PROTAC molecule. Mechanism research showed that X1–4P-MDM2 formed a ternary complex with DYRK1A and murine double minute 2 (MDM2), and induced the degradation of DYRK1A through the ubiquitin-proteasome system pathway. At a dose much lower than that of DMB, X1–4P-MDM2 still significantly enhanced β-cell proliferation by inhibiting transforming growth factor beta (TGF-β) and promoting the mitogen-activated protein kinases/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway, which may provide a new strategy for the application of DMB in diabetes.

FUT6 Suppresses the Proliferation, Migration, Invasion, and Epithelial-Mesenchymal Transition of Esophageal Carcinoma Cells via the Epidermal Growth Factor Receptor/Extracellular Signal-Regulated Kinase Signaling Pathway.

Esophageal cancer (ESCA) is a high-incidence disease worldwide, of which the 5-year survival rate remains dismal since the cellular basis of ESCA remains largely unclear. Herein, we attempted to examine the manifestation of fucosyltransferase-6 (FUT6) in ESCA and the associated mechanisms. The GSE161533 dataset was used to analyze a crucial gene in ESCA. The expression of FUT6 was investigated in normal esophageal epithelial cells and ESCA cell lines. Following FUT6 knockdown or overexpression, cell proliferation, migration, invasion, and levels of epithelial–mesenchymal transition (EMT)-related and epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) signaling pathway-related proteins were evaluated using CCK-8, Transwell, and Western blotting with antibodies against EGFR, p-EGFR, E-cadherin, Vimentin, N-cadherin, ERK1/2, and p-ERK1/2), respectively. EGF was administered to stimulate the EGFR/ERK signaling pathway, followed by the assessment of cellular activity. Database analysis revealed that FUT6 was downregulated in the ESCA cells. Our study indicated that FUT6 is suppressed in various ESCA cell lines. Moreover, cell proliferation, invasion, migration, and EMT-related protein levels were conspicuously enhanced or restrained by FUT6 disruption or overexpression. FUT6 overexpression suppressed the malignant activities of the cells when stimulated by EGF, including inhibition of cell growth, movement, invasion, and EMT advancement, as well the reduction the levels of EGFR/ERK pathway proteins. In conclusion, FUT6 can suppress the EGFR/ERK signaling pathway activated by EGF, leading to the potential attenuation of ESCA cell proliferation, invasion, migration, and EMT.

Time-dependent effects of BRAF-V600E on cell cycling, metabolism, and function in engineered myocardium.

Candidate cardiomyocyte (CM) mitogens such as those affecting the extracellular signal-regulated kinase (ERK) signaling pathway represent potential targets for functional heart regeneration. We explored whether activating ERK via a constitutively active mutant of B-raf proto-oncogene (BRAF), BRAF-V600E (caBRAF), can induce proproliferative effects in neonatal rat engineered cardiac tissues (ECTs). Sustained CM-specific caBRAF expression induced chronic ERK activation, substantial tissue growth, deficit in sarcomeres and contractile function, and tissue stiffening, all of which persisted for at least 4 weeks of culture. caBRAF-expressing CMs in ECTs exhibited broad transcriptomic changes, shift to glycolytic metabolism, loss of connexin-43, and a promigratory phenotype. Transient, doxycycline-controlled caBRAF expression revealed that the induction of CM cycling is rapid and precedes functional decline, and the effects are reversible only with short-lived ERK activation. Together, direct activation of the BRAF kinase is sufficient to modulate CM cycling and functional phenotype, offering mechanistic insights into roles of ERK signaling in the context of cardiac development and regeneration.

Retracted: Analysis of Antiapoptosis Effect of Netrin-1 on Ischemic Stroke and Its Molecular Mechanism under Deleted in Colon Cancer/Extracellular Signal-Regulated Kinase Signaling Pathway.

[This retracts the article DOI: 10.1155/2020/8855949.].

Exploring the Neuroprotective Effects of Lithium in Ischemic Stroke: A literature review.

Ischemic stroke ranks among the foremost clinical causes of mortality and disability, instigating neuronal degeneration, fatalities, and various sequelae. While standard treatments, such as intravenous thrombolysis and endovascular thrombectomy, prove effective, they come with limitations. Hence, there is a compelling need to develop neuroprotective agents capable of improving the functional outcomes of the nervous system. Numerous preclinical studies have demonstrated that lithium can act in multiple molecular pathways, including glycogen synthase kinase 3(GSK-3), the Wnt signaling pathway, the mitogen-activated protein kinase (MAPK)/ extracellular signal-regulated kinase (ERK) signaling pathway, brain-derived neurotrophic factor (BDNF), mammalian target of rapamycin (mTOR), and glutamate receptors. Through these pathways, lithium has been shown to affect inflammation, autophagy, apoptosis, ferroptosis, excitotoxicity, and other pathological processes, thereby improving central nervous system (CNS) damage caused by ischemic stroke. Despite these promising preclinical findings, the number of clinical trials exploring lithium's efficacy remains limited. Additional trials are imperative to thoroughly ascertain the effectiveness and safety of lithium in clinical settings. This review delineates the mechanisms underpinning lithium's neuroprotective capabilities in the context of ischemic stroke. It elucidates the intricate interplay between these mechanisms and sheds light on the involvement of mitochondrial dysfunction and inflammatory markers in the pathophysiology of ischemic stroke. Furthermore, the review offers directions for future research, thereby advancing the understanding of the potential therapeutic utility of lithium and establishing a theoretical foundation for its clinical application.

Streptolysin S induces proinflammatory cytokine expression in calcium ion-influx-dependent manner

Anginosus group streptococci (AGS) are opportunistic pathogens that reside in the human oral cavity. The β-hemolytic strains of Streptococcus anginosus subsp. anginosus (SAA) produce streptolysin S (SLS), a streptococcal peptide hemolysin. In recent clinical scenarios, AGS, including this species, have frequently been isolated from infections and disorders beyond those in the oral cavity. Consequently, investigating this situation will reveal the potential pathogenicity of AGS to ectopic infections in humans. However, the precise mechanism underlying the cellular response induced by secreted SLS and its relevance to the pathogenicity of AGS strains remain largely unknown. This study aims to elucidate the mechanism underlying the host cellular response of the human acute monocytic leukemia cell line THP-1 to secreted SLS. In THP-1 cells incubated with the culture supernatant of β-hemolytic SAA containing SLS as the sole cytotoxic factor, increased Ca2+ influx and elevated expression of proinflammatory cytokines were observed. Significantly reduced expression of SLS-dependent upregulated cytokine genes under Ca2+-chelating conditions suggests that Ca2+ influx triggers SLS-dependent cellular responses. Furthermore, SLS-dependent enhanced expression of IL-8 was also implicated in the activation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways. The findings presented in this study are crucial for a comprehensive understanding of the real pathogenicity of SLS-producing β-hemolytic AGS in the latest clinical situations.

Circ_0053943 complexed with IGF2BP3 drives uveal melanoma progression via regulating N6-methyladenosine modification of Epidermal growth factor receptor.

Numerous studies have characterized the critical role of circular RNAs (circRNAs) as regulatory factors in the progression of multiple cancers. However, the biological functions of circRNAs and their underlying molecular mechanisms in the progression of uveal melanoma (UM) remain enigmatic. In this study, we identified a novel circRNA, circ_0053943, through re-analysis of UM microarray data and quantitative RT-PCR. Circ_0053943 was found to be upregulated in UM and to promote the proliferation and metastatic ability of UM cells in both in vitro and in vivo settings. Mechanistically, circ_0053943 was observed to bind to the KH1 and KH2 domains of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), thereby enhancing the function of IGF2BP3 by stabilizing its target mRNA. RNA sequencing assays identified epidermal growth factor receptor (EGFR) as a target gene of circ_0053943 and IGF2BP3 at the transcriptional level. Rescue assays demonstrated that circ_0053943 exerts its biological function by stabilizing EGFR mRNA and regulating the downstream mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway. Collectively, circ_0053943 may promote UM progression by stabilizing EGFR mRNA and activating the MAPK/ERK signaling pathway through the formation of a circ_0053943/IGF2BP3/EGFR RNA-protein ternary complex, thus providing a potential biomarker and therapeutic target for UM.