Kinase Signaling Research Articles

Electrochemical Mineralization Regulates Hydroxyapatite Deposition of Silk Fibroin Nanofibers for Promoting Osteogenic Differentiation of Human Mesenchymal Stem Cells

ABSTRACTScaffold and stem cells are the key elements in the procedure of bone repair. Bombyx mori silk fibroin (SF) is the proper material for bone tissue engineering due to its biocompatibility and its easy to obtain nanofiber structure. The suitable cell substrate is also an important factor because different cells have different adaptations to composite. For this case, selecting a scaffold that can promote osteogenic differentiation of various cells is crucial and meaningful. In this work, hydroxyapatite (HA) was deposited precisely onto each silk nanofiber by electrochemical mineralization (EC) to form SF/HA. SF/HA can promote the proliferation and osteogenic differentiation of both human bone marrow mesenchymal‐derived stem cells (hMSCs) and human adipose‐derived mesenchymal stem cells (hAMSCs). It also promot the expression of alkaline phosphatase (ALP) and osteogenic differentiation related genes. Western blot analyses show mitogen‐activated protein kinase (MAPK) signal pathway is regulated by SF/HA. Therefore, the study provides a proper method to obtain a good composite SF/HA and it promotes the osteogenic differentiation of both hMSCs and hAMSCs.

Melatonin-mediated low-temperature tolerance of cucumber seedlings requires Ca2+/CPKs signaling pathway

Melatonin (Mel) is recognized as a prominent plant growth regulator. This study investigated the alleviating effect of Mel pretreatment on growth inhibition caused by low-temperature (LT) stress (10 °C/6 °C) in cucumber seedlings and explored the role of the Ca2+/Calcium-dependent protein kinases (CPKs) signaling pathway in Mel-regulated LT tolerance. The main results are as follows: compared to LT treatment alone, 100 μM Mel increased both the content of Ca2+ (highest about 42.01%) and the expression levels of Ca2+ transporter and cyclic nucleotide-gated channel (CNGC) genes under LT. Similarly, Mel enhanced the content of CPKs (highest about 27.49%) and the expression levels of CPKs family genes in cucumber leaves under LT. Additionally, pretreatment with 100 μM Mel for three days strengthened the antioxidant defense and photosynthesis of seedlings under LT. Genes in the ICE-CBF-COR pathway and the MAPK cascade were upregulated by Mel, with maximum upregulations reaching approximately 2.5-fold and 1.9-fold, respectively, thus conferring LT tolerance to cucumber seedlings. However, the above beneficial effects of Mel were weakened by co-treatment with calcium signaling blockers (LaCl3 or EGTA) or CPKs inhibitors (TFP or W-7), suggesting that the Ca2+/CPKs pathway is involved in the Mel-mediated regulation of LT tolerance. In conclusion, this study revealed that Mel can alleviate growth inhibition in cucumber seedlings under LT stress and demonstrated that the Ca2+/CPKs signaling pathway is crucial for the Mel-mediated enhancement of LT tolerance. The findings hold promise for providing theoretical insights into the application of Mel in agricultural production and for investigating its underlying mechanisms of action.

CRABP2 promotes cell migration and invasion by activating PI3K/AKT and MAPK signalling pathways via upregulating LAMB3 in prostate cancer.

Prostate cancer (PCa) has become a worldwide health burden among men. Previous studies have suggested that cellular retinoic acid binding protein 2 (CRABP2) significantly affects the regulation of cell proliferation, motility and apoptosis in multiple cancers; however, the effect of CRABP2 on PCa is poorly reported. CRABP2 expression in different PCa cell lines and its effect on different cellular functions varied. While CRABP2 promotes cell migration and invasion, it appears to inhibit cell proliferation specifically in PC-3 cells. However, the proliferation of DU145 and 22RV1 cells did not appear to be significantly affected by CRABP2. Additionally, CRABP2 had no influence on the cell cycle distribution of PCa cells. The RNA-seq assay showed that overexpressing CRABP2 upregulated laminin subunit beta-3 (LAMB3) mRNA expression, and the enrichment analyses revealed that the differentially expressed genes were enriched in the phosphoinositide 3-kinase (PI3K)/activated protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) signalling pathways. The following western blot experiments also confirmed the upregulated LAMB3 protein level and the activation of the PI3K/AKT and MAPK signalling pathways. Moreover, overexpressing CRABP2 significantly inhibited tumour growth in vivo. In conclusion, CRABP2 facilitates cell migration and invasion by activating PI3K/AKT and MAPK signalling pathways through upregulating LAMB3 in PCa.

Profiling Cellular Morphological Changes Induced by Dual-Targeting PROTACs of Aurora Kinase and RNA-Binding Protein YTHDF2.

Proteolysis targeting chimeras (PROTACs) are new chemical modalities that degrade proteins of interest, including established kinase targets and emerging RNA-binding proteins (RBPs). Whereas diverse sets of biochemical, biophysical and cellular assays are available for the evaluation and optimizations of PROTACs in understanding the involved ubiquitin-proteasome-mediated degradation mechanism and the structure-degradation relationship, a phenotypic method profiling the cellular morphological changes is rarely used. In this study, first, we reported the only examples of PROTACs degrading the mRNA-binding protein YTHDF2 via screening of multikinase PROTACs. Second, we reported the profiling of cellular morphological changes of the dual kinase- and RBP-targeting PROTACs using the unbiased cell painting assay (CPA). The CPA analysis revealed the high biosimilarity with the established aurora kinase cluster and annotated aurora kinase inhibitors, which reflected the association between YTHDF2 and the aurora kinase signaling network. Broadly, the results demonstrated that the cell painting assay can be a straightforward and powerful approach to evaluate PROTACs. Complementary to the existing biochemical, biophysical and cellular assays, CPA provided a new perspective in characterizing PROTACs at the cellular morphology.

Research on the mechanism of shengxian and jinshuiliujun decoction in treating silicosis based on network pharmacology

Objective: To explore the active ingredients of shengxian and jinshuiliujun decoction with the method of network pharmacology, and to verify the experimental mechanism of its treatment of silicosis. Methods: In May 2023, the active ingredients and targets of drugs in shengxian and jinshuiliujun decoction were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) database. The target of silicosis disease was screened by databases such as Genecards, Disease Gene Network (DisGeNET), Comparative Toxicogenomics Database (CTD), etc. The screened drug targets and disease targets were intersected to obtain the target set of shengxian and jinshuiliujun decoction for the treatment of silicosis. Protein-protein interaction (PPI) network analysis was performed on the target set through STRING database, and core target genes were screened. GO enrichment analysis and KEGG pathway analysis of intersection genes were performed based on Metascape database, and molecular docking verification of key components and targets of shengxian and jinshuiliujun decoction was carried out. Twenty-four adult male SD rats with SPF grade were randomly divided into control group, model group and TCM intervention group, with 8 rats in each group. The dust-stained rat model was prepared by non-tracheal exposure of 1 ml silica suspension (50 mg/ml) in one go, and TCM intervention group was given shengxian and jinshuiliujun decoction[6 g/ (kg·d) ] on the second day. The CT of the lungs of each group was observed 28 days after the dust-stained rat model. Paraffin sections of rat lung tissues were prepared and stained with Hematoxylin-Eosin (HE) and Masson. Western blot was used to verify the expression of core target-related proteins in rat lung tissues after the intervention of shengxian and jinshuiliujun decoction for 28 days, and the differences in protein expression between groups were compared by one-way analysis of variance. Results: A total of 205 active ingredients and 3345 active compounds were selected from shengxian and jinshuiliujun decoction, corresponding to 281 targets, among which 240 targets were related to silicosis. Serine/threonine kinase 1 (AKT1), tumor protein p53 (TP53), tumor necrosis factor (TNF) and interleukin (IL) 6 may be the key targets of shengxian and jinshuiliujun decoction in the treatment of silicosis. Through enrichment analysis, 30 GO entries and 20 potential signaling pathways were screened according to P-value, including nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK) and cancer signaling pathways. Molecular docking showed that the active compounds of shengxian and jinshuiliujun decoction had good binding with the core target proteins, and the strongest binding properties were beta-sitosterol and TNF-α (-10.45 kcal/mol). In animal experiments, the inflammatory infiltration and fibrosis of lung tissue of rats in TCM intervention group were significantly improved. Compared with control group, the levels of TNF-α, IL-1β, IL-6 and NF-κB in lung tissue of model group were significantly increased (P<0.05). Compared with model group, the lung injury of rats in TCM intervention group was significantly improved, and the expressions of TNF-α, IL-1β, IL-6 and NF-κB were significantly decreased (P<0.05) . Conclusion: Shengxian and jinshuiliujun decoction in the treatment of silicosis may play an anti-fibrosis role by inhibiting the NF-κB signal transduction pathway mediated by inflammatory factors such as TNF-α and IL-1β, which provides a reference for further exploring the material basis and mechanism of its action.

Comprehensive analysis of MAPK genes in the prognosis, immune characteristics, and drug treatment of renal clear cell carcinoma using bioinformatic analysis and Mendelian randomization

Mitogen-activated protein kinase (MAPK) signalling is vitally important in tumour development and progression. This study is the first to comprehensively analyse the role of MAPK-family genes in the progression, prognosis, immune-cell infiltration, methylation, and potential therapeutic value drug candidates in ccRCC. We identified a novel prognostic panel of six MAPK-signature genes (MAP3K12, MAP3K1, MAP3K5, MAPK1, MAPK8, MAPK9), and introduced a robust MAPK-signature risk model for predicting ccRCC prognosis. Model construction, evaluation, and external validation using datasets from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database demonstrated its stability, as well as high sensitivity and specificity. Enrichment analysis suggested the participation of immune-mediated mechanism in MAPK dysregulation in ccRCC. Immune-infiltration analysis confirmed the relationship and revealed that the MAPK-signature risk model might stratify immunotherapy response in ccRCC, which was verified in drug sensitivity analysis and validated in external ccRCC immunotherapy dataset (GSE67501). Potential therapeutic drug predictions for key MAPKs using DSigDB, Network Analyst, CTD, and DGIdb were subsequently verified by molecular docking with AutoDock Vina and PyMol. Mendelian randomization further demonstrated the possibilities of the MAPK-signature genes as targets for therapeutic drugs in ccRCC. Methylation analysis using UALCAN and MethSurv revealed the participation of epigenetic modifications in dysregulation and survival difference of MAPK pathway in ccRCC. Among the key MAPKs, MAP3K12 exhibited the highest significance, indicating its independent prognostic value as single gene in ccRCC. Knockout and overexpression validation experiments in vitro and in vivo found that MAP3K12 acted as a promoter of tumour progression in RCC, suggesting a pivotal role for MAP3K12 in the proliferation, migration, and invasion of RCC cells. Our findings proposed the potential of MAPK-signature genes as biomarkers for prognosis and therapy response, as well as targets for therapeutic drugs in ccRCC.

LILRB1-HLA-G axis defines a checkpoint driving natural killer cell exhaustion in tuberculosis

Chronic infections, including Mycobacterium tuberculosis (Mtb)-caused tuberculosis (TB), can induce host immune exhaustion. However, the key checkpoint molecules involved in this process and the underlying regulatory mechanisms remain largely undefined, which impede the application of checkpoint-based immunotherapy in infectious diseases. Here, through adopting time-of-flight mass cytometry and transcriptional profiling to systematically analyze natural killer (NK) cell surface receptors, we identify leukocyte immunoglobulin like receptor B1 (LILRB1) as a critical checkpoint receptor that defines a TB-associated cell subset (LILRB1+ NK cells) and drives NK cell exhaustion in TB. Mechanistically, Mtb-infected macrophages display high expression of human leukocyte antigen-G (HLA-G), which upregulates and activates LILRB1 on NK cells to impair their functions by inhibiting mitogen-activated protein kinase (MAPK) signaling via tyrosine phosphatases SHP1/2. Furthermore, LILRB1 blockade restores NK cell-dependent anti-Mtb immunity in immuno-humanized mice. Thus, LILRB1-HLA-G axis constitutes a NK cell immune checkpoint in TB and serves as a promising immunotherapy target.

The effect of overexpression of CyPA on gene expression in human umbilical vein endothelial cells.

The aim of this study is to screen the differentially expressed genes and genes with alternative splicing in PPIA overexpressing cells by transcriptome sequencing. Transcriptome sequencing was performed to identify differentially expressed genes and genes with altered alternative splicing in PPIA overexpressing cells and results were validated by real-time quantitative polymerase chain reaction. The biological function and pathways of those genes were further explored through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses. A total of 157 significantly upregulated genes and 171 significantly downregulated genes were identified in PPIA overexpressing cells, and the splicing pattern of LHPP, APH1A, BRD1, and ORAI3 was found to be altered. GO analyses showed that the most enriched GO terms of the 157 upregulated genes included extracellular region, protein binding, and metal ion, and the most enriched GO terms of the 171 downregulated genes included binding neuron projection, protein binding, and endoplasmic reticulum unfolded protein response. Kyoto Encyclopedia of Genes and Genomes analyses showed that the 157 upregulated genes were mainly enriched in gastric acid secretion, Mitogen-activated protein kinase signaling pathway, etc, and the 171 downregulated genes were mainly enriched in transcriptional misregulation in cancer, Tumor necrosis factor signaling pathway, etc. The overexpression of PPIA in human umbilical vein endothelial cells causes changes in the expression of downstream genes and induces alternative splicing in multiple genes. PPIA alters the expression or the alternative splicing pattern of downstream genes, leading to pathogenesis of vascular endothelial injury by high glucose mediated through CyPA.

SIRT3/AMPK Signaling Pathway Regulates Lipid Metabolism and Improves Vulnerability to Atrial Fibrillation in Dahl Salt-Sensitive Rats.

Hypertension may result in atrial fibrillation (AF) and lipid metabolism disorders. The Sirtuins3 (SIRT3)/AMP-activated protein kinase (AMPK) signaling pathway has the capacity to regulate lipid metabolism disorders and the onset of AF. We hypothesize that the SIRT3/AMPK signaling pathway suppresses lipid metabolism disorders, thereby mitigating salt-sensitive hypertension (SSHT)-induced susceptibility to AF. The study involved 7-week-old male Dahl salt-sensitive that were fed either a high-salt diet (8% NaCl; DSH group) or a normal diet (0.3% NaCl; DSN group). Then DSH group was administered either oral metformin (MET, an AMPK agonist) or intraperitoneal injection of Honokiol (HK, a SIRT3 agonist). This experimental model allowed for the measurement of Systolic blood pressure (SBP), the expression levels of lipid metabolism-related biomarkers, pathological examination of atrial fibrosis, and lipid accumulation, as well as AF inducibility and AF duration. DSH decrease SIRT3, phosphorylation-AMPK, and very long-chain acyl-CoA dehydrogenase, (VLCAD) expression, increased FASN and FABP4 expression and concentrations of free fatty acid and triglyceride, atrial fibrosis and lipid accumulation in atrial tissue, enhanced level of SBP, promoted AF induction rate and prolonged AF duration, which are blocked by MET and HK. Our results also showed that the degree of atrial fibrosis was negatively correlated with VLCAD expression, but positively correlated with the expression of FASN and FABP4. We have confirmed that a high-salt diet can result in hypertension, and associated atrial tissue lipid metabolism dysfunction. This condition is linked to the inhibition of the SIRT3/AMPK signaling pathway, which plays a significant role in the progression of susceptibility to AF in SSHT rats.

Maternal administration of APAP induces angiogenesis disorders in mouse placenta via SOCS3/JAK1/STAT3 pathway

Acetaminophen (APAP, also known as paracetamol) is a commonly used antipyretic and analgesic that is considered safe to use during pregnancy. However, a growing body of research indicates that gestational administration of APAP increased the risk of neurodevelopmental, reproductive and genitourinary disorders in offspring, alongside impairments in placental development. Notably, over-dosed APAP exhibits direct toxicity to endothelial cells, but there is very limited research investigating the impact of APAP on placental angiogenesis, a gap we aim to address in this study. Pregnant mice were gavaged with APAP (15, 50 and 150 mg/kg/d) from embryonic day 11.5 (E11.5) to E13.5. Administration of 150 mg/kg/d APAP leads to low birth weight (LBW) of the offspring and disordered vascular structures within the labyrinthine (Lab) layer of the placenta. This disruption is accompanied by a significant increase in Suppressor of Cytokine Signaling 3 (SOCS3) level, a negative regulator of the Janus kinase signal transducer 1 and activator of the transcription 3 (JAK1/STAT3) signaling. Meanwhile, Human umbilical vein endothelial Cells (HUVECs) with the treatment of 3 mM APAP exhibited reduced cell viability, whereas 1 mM APAP significantly affected the proliferation, migration, invasion and angiogenic capacities of HUVECs. Further, SOCS3 was up-regulated in HUVECs, accompanied by inhibition of JAK1/STAT3 pathways. Knocking-down SOCS3 in HUVECs restored the nuclear translocation of STAT3 and efficiently promoted cellular capacity of tube formation. Overall, short-term maternal administration of overdosed APAP impairs angiogenic capacities of fetal endothelial cells via SOCS3/JAK1/STAT3 pathway in the mouse placenta. This study reveals that overdose of APAP during pregnancy may adversely affect placental angiogenesis, emphasizing the importance of adhering to the safe principles of smallest effective dose for the shortest required durations.

Ripening and rot: How ripening processes influence disease susceptibility in fleshy fruits.

Fleshy fruits become more susceptible to pathogen infection when they ripen; for example, changes in cell wall properties related to softening make it easier for pathogens to infect fruits. The need for high-quality fruit has driven extensive research on improving pathogen resistance in important fruit crops such as tomato (Solanum lycopersicum). In this review, we summarize current progress in understanding how changes in fruit properties during ripening affect infection by pathogens. These changes affect physical barriers that limit pathogen entry, such as the fruit epidermis and its cuticle, along with other defenses that limit pathogen growth, such as preformed and induced defense compounds. The plant immune system also protects ripening fruit by recognizing pathogens and initiating defense responses involving reactive oxygen species production, mitogen-activated protein kinase signaling cascades, and jasmonic acid, salicylic acid, ethylene, and abscisic acid signaling. These phytohormones regulate an intricate web of transcription factors (TFs) that activate resistance mechanisms, including the expression of pathogenesis-related genes. In tomato, ripening regulators, such as RIPENING INHIBITOR and NON_RIPENING, not only regulate ripening but also influence fruit defenses against pathogens. Moreover, members of the ETHYLENE RESPONSE FACTOR (ERF) family play pivotal and distinct roles in ripening and defense, with different members being regulated by different phytohormones. We also discuss the interaction of ripening-related and defense-related TFs with the Mediator transcription complex. As the ripening processes in climacteric and non-climacteric fruits share many similarities, these processes have broad applications across fruiting crops. Further research on the individual contributions of ERFs and other TFs will inform efforts to diminish disease susceptibility in ripe fruit, satisfy the growing demand for high-quality fruit and decrease food waste and related economic losses.

Multi-omics analysis of green lineage osmotic stress pathways unveils crucial roles of different cellular compartments

Maintenance of water homeostasis is a fundamental cellular process required by all living organisms. Here, we use the single-celled green alga Chlamydomonas reinhardtii to establish a foundational understanding of osmotic-stress signaling pathways through transcriptomics, phosphoproteomics, and functional genomics approaches. Comparison of pathways identified through these analyses with yeast and Arabidopsis allows us to infer their evolutionary conservation and divergence across these lineages. 76 genes, acting across diverse cellular compartments, were found to be important for osmotic-stress tolerance in Chlamydomonas through their functions in cytoskeletal organization, potassium transport, vesicle trafficking, mitogen-activated protein kinase and chloroplast signaling. We show that homologs for five of these genes have conserved functions in stress tolerance in Arabidopsis and reveal a novel PROFILIN-dependent stage of acclimation affecting the actin cytoskeleton that ensures tissue integrity upon osmotic stress. This study highlights the conservation of the stress response in algae and land plants, and establishes Chlamydomonas as a unicellular plant model system to dissect the osmotic stress signaling pathway.

Vitamin C inactivates c-Jun N-terminal kinase to stabilize heart and neural crest derivatives expressed 1 (Hand1) in regulating placentation and maintenance of pregnancy

Vitamin C (VC) serves as a pivotal nutrient for anti-oxidation process, metabolic responses, and stem cell differentiation. However, its precise contribution to placenta development and gestation remains obscure. Here, we demonstrated that physiological levels of VC act to stabilize Hand1, a key bHLH transcription factor vital for the development trajectory of trophoblast giant cell (TGC) lineages, thereby promoting the differentiation of trophoblast stem cells into TGC. Specifically, VC administration inactivated c-Jun N-terminal kinase (JNK) signaling, which directly phosphorylates Hand1 at Ser48, triggering the proteasomal degradation of Hand1. Conversely, a loss-of-function mutation at Ser48 on Hand1 not only significantly diminished both intrinsic and VC-induced stabilization of Hand1 but also underscored the indispensability of this residue. Noteworthy, the insufficiency of VC led to severe defects in the differentiation of diverse TGC subtypes and the formation of labyrinth's vascular network in rodent placentas, resulting in failure of maintenance of pregnancy. Importantly, VC deficiency, lentiviral knockdown of JNK or overexpression of Hand1 mutants in trophectoderm substantially affected the differentiation of primary and secondary TGC in E8.5 mouse placentas. Thus, these findings uncover the significance of JNK inactivation and consequential stabilization of Hand1 as a hitherto uncharacterized mechanism controlling VC-mediated placentation and perhaps maintenance of pregnancy.Graphical

ERK signalling eliminates Nanog and maintains Oct4 to drive the formative pluripotency transition.

Naïve epiblast cells in the embryo and pluripotent stem cells in vitro undergo developmental progression to a formative state competent for lineage specification. During this transition, transcription factors and chromatin are rewired to encode new functional features. Here, we examine the role of mitogen-activated protein kinase (ERK1/2) signalling in pluripotent state transition. We show that a primary consequence of ERK activation in mouse embryonic stem cells is elimination of Nanog, which precipitates breakdown of the naïve state gene regulatory network. Variability in pERK dynamics results in heterogeneous loss of Nanog and metachronous state transition. Knockdown of Nanog allows exit without ERK activation. However, transition to formative pluripotency does not proceed and cells collapse to an indeterminate identity. This outcome is due to failure to maintain expression of the central pluripotency factor Oct4. Thus, during formative transition ERK signalling both dismantles the naïve state and preserves pluripotency. These results illustrate how a single signalling pathway can both initiate and secure transition between cell states.

Focal adhesion kinase signaling - tumor vulnerabilities and clinical opportunities.

Focal adhesion kinase (FAK; encoded by PTK2) was discovered over 30 years ago as a cytoplasmic protein tyrosine kinase that is localized to cell adhesion sites, where it is activated by integrin receptor binding to extracellular matrix proteins. FAK is ubiquitously expressed and functions as a signaling scaffold for a variety of proteins at adhesions and in the cell cytoplasm, and with transcription factors in the nucleus. FAK expression and intrinsic activity are essential for mouse development, with molecular connections to cell motility, cell survival and gene expression. Notably, elevated FAK tyrosine phosphorylation is common in tumors, including pancreatic and ovarian cancers, where it is associated with decreased survival. Small molecule and orally available FAK inhibitors show on-target inhibition in tumor and stromal cells with effects on chemotherapy resistance, stromal fibrosis and tumor microenvironment immune function. Herein, we discuss recent insights regarding mechanisms of FAK activation and signaling, its roles as a cytoplasmic and nuclear scaffold, and the tumor-intrinsic and -extrinsic effects of FAK inhibitors. We also discuss results from ongoing and advanced clinical trials targeting FAK in low- and high-grade serous ovarian cancers, where FAK acts as a master regulator of drug resistance. Although FAK is not known to be mutationally activated, preventing FAK activity has revealed multiple tumor vulnerabilities that support expanding clinical combinatorial targeting possibilities.

DEPDC1 affects autophagy-dependent glycolysis levels in human osteosarcoma cells by modulating RAS/ERK signaling through TTK.

The current treatment for osteosarcoma (OS) is based on surgery combined with systemic chemotherapy, however, gene therapy has been hypothesized to improve patient survival rates. The density-enhanced protein domain 1 protein (DEPDC1) functions as a crucial determinant in the advancement of OS, which is highly expressed in OS cells. The current study was designed to delve into the effect and mechanism of DEPDC1 and phosphotyrosine-picked threonine tyrosine kinase (TTK) in OS. The expression of DEPDC1 and TTK in OS cells was detected by western blotting. Furthermore, the assessment of glycolysis encompassed the quantification of extracellular acidification rate, glucose uptake rate, lactate concentration, and the expression of glucose transporter 1, hexokinase 2, and pyruvate kinase M2. Finally, the functions of DEPDC1 and TTK in autophagy and ras-extracellular signal-regulated kinase signaling were determined by western blotting after interfering with DEPDC1 in SaOS-2 cells. The results revealed that DEPDC1 and TTK were upregulated in OS cell lines and interfering with DEPDC1 inhibited glycolysis and autophagy in OS cells. Furthermore, the STRING database suggested that DEPDC1 and TTK perform targeted binding. Notably, the results of the present study revealed that DEPDC1 upregulated RAS expression through TTK and enhanced ERK activity, thereby affecting glycolysis and autophagy in OS cells. Collectively, the present investigation demonstrated that DEPDC1 affected autophagy-dependent glycolysis levels of OS cells by regulating RAS/ERK signaling through TTK.

Expression of the non-coding RNA nc886 facilitates the development of tyrosine kinase inhibitor resistance in EGFR-mutated non-small-cell lung cancer cells

Treatment of non-small-cell lung cancer (NSCLC) patients possessing EGFR-activating mutations with tyrosine kinase inhibitors (TKIs) can confer an initial promising response. However, TKI resistance inevitably arises. Numerous TKI resistance mechanisms are identified including EGFR secondary mutations, bypass receptor tyrosine kinase (RTK) signaling, and cellular transition e.g. epithelial-mesenchymal transition (EMT). To increase the knowledge of TKI resistance we performed an epigenetic screen to identify small non-coding (nc) genes with DNA methylation alterations in HCC827 NSCLC EGFR-mutated cells with acquired TKI resistance. We analyzed Infinium Methylation EPIC 850K Array data for DNA methylation changes present in both TKI-resistant HCC827 cells with EMT and MET-amplification. Hereby, we identified that the polymorphic maternal imprinted gene nc886 (vtRNA2-1) has a decrease in promoter DNA methylation in TKI-resistant cells. This epigenetic change was associated with an increase in the expression of nc886. The induction of EMT did not affect nc886 expression. CRISPR/Cas9-mediated distortion of the nc886 sequence increased the sensitivity of HCC827 cells towards TKI. Finally, nc886 sequence distortion hindered MET RTK activation and instead was EMT the endpoint TKI resistance mechanism. In conclusion, the expression of nc886 contributes to TKI resistance in the HCC827 NSCLC cell line by supporting cell survival and selection of the endpoint TKI resistance mechanism. We propose DNA methylation and expression changes for nc886 to constitute a novel TKI resistance contributing mechanism in NSCLC.

Dual Inhibition of PI3 Kinase and MAP Kinase Signaling Pathways in Intrahepatic Cholangiocellular Carcinoma Cell Lines Leads to Proliferation Arrest but Not Apoptosis.

Cholangiocellular carcinoma (CCA) is the second most common primary liver cancer, with increasing incidence worldwide and inadequate therapeutic options. Intra- and extrahepatic bile ducts have distinctly different embryonic origins and developmental behavior, and accordingly, intra- and extrahepatic CCAs (ICC vs. ECC) are molecularly different. A promising strategy in oncotherapy is targeted therapy, targeting proteins that regulate cell survival and proliferation, such as the MAPK/ERK and PI3K/AKT/mTOR signaling pathways. Inhibitors of these pathways have been tested previously in CCA cell lines. However, these cell lines could not be clearly assigned to ICC or ECC, and the results indicated apoptosis induction by targeted therapeutics. We tested targeted therapeutics (selumetinib, MK2206) in three defined ICC cell lines (HuH28, RBE, SSP25). We observed additive effects of the dual inhibition of the two pathways, in accordance with the inhibition of phospho-AKT and phospho-ERK1/2 expression. Proliferation was blocked more effectively with dual inhibition than with each single inhibition, but cell numbers did not drop below baseline. Accordingly, we observed G1 phase arrest but not apoptosis or cell death (measured by cleaved caspase-3, AIFM1 regulation, sub-G0/G1 phase). We conclude that the dual inhibition of the MAPK/ERK and PI3K/AKT/mTOR pathways is highly effective to block the proliferation of ICC cell lines in vitro; however, potential clinical applications must be critically examined, as a proliferation block could also induce resistance to standard therapies.

Shifts in keratin isoform expression activate motility signals during wound healing

Keratin intermediate filaments confer structural stability to epithelial tissues, but the reason this simple mechanical function requires a protein family with 54 isoforms is not understood. During skin wound healing, a shift in keratin isoform expression alters the composition of keratin filaments. If and how this change modulates cellular functions that support epidermal remodeling remains unclear. We report an unexpected effect of keratin isoform variation on kinase signal transduction. Increased expression of wound-associated keratin 6A, but not of steady-state keratin 5, potentiated keratinocyte migration and wound closure without compromising mechanical stability by activating myosin motors to increase contractile force generation. These results substantially expand the functional repertoire of intermediate filaments from their canonical role as mechanical scaffolds to include roles as isoform-tuned signaling scaffolds that organize signal transduction cascades in space and time to influence epithelial cell state.

Recurrent RhoGAP gene fusion CLDN18-ARHGAP26 promotes RHOA activation and focal adhesion kinase and YAP-TEAD signalling in diffuse gastric cancer

ObjectiveGenomic studies of gastric cancer have identified highly recurrent genomic alterations impacting RHO signalling, especially in the diffuse gastric cancer (DGC) histological subtype. Among these alterations are interchromosomal translations leading...