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PubMed2002

The role of c-erbB receptors and ligands in head and neck squamous cell carcinoma.

c-erbB receptor signalling induces pleiotropic responses and influences several biological functions involved in the pathogenesis and progression of HNSCC. Aberrant expression of multiple c-erbB receptors and ligands is frequently observed in tumour cells. EGFR appears to be a dominant factor controlling the malignant phenotype in HNSCC at least in part via regulation of molecules involved in invasive and angio-/lymphangiogenic processes. Although c-erbB-2 is an orphan receptor, the formation of heterodimer complexes appears to be an important mechanism for inter-receptor activation and synergistic signal transduction. The roles of c-erbB-3 and c-erbB-4 in HNSCC progression are less clear. However, their ability to form heterodimers with other c-erbB family members enhances proliferation and invasion in HNSCC cells. At least two major downstream signalling pathways, MAPK and PI3K, are involved in the transcriptional regulation of proteases and cytokines implicated in invasion and angiogenesis. Studies using clinical specimens confirmed experimental data that co-operative signalling of c-erbB receptors may play a significant role in the pathogenesis of HNSCC. Most therapeutic studies in HNSCC so far have focused on the strategies targeting of EGFR. Due to the complexity of the system both at the receptor and ligand levels and the integrated biological functions of the c-erbB family in HNSCC, the effect of combined c-erbB blockade (or their downstream signalling pathways) on HNSCC progression should be explored.

Carcinoma, Squamous Cell↗
PubMed2026

Zhiling Jiangya decoction treats hypertension in rats: An integrative study of network pharmacology, immune infiltration, molecular simulation, and 16S rDNA sequencing.

OBJECTIVE: This study integrated network pharmacology, immune infiltration analysis, molecular docking, molecular dynamics simulation, ADMET prediction, 16S rDNA sequencing, and rat experiments to elucidate the potential mechanisms underlying the antihypertensive effects of Zhiling Jiangya Decoction (ZLJYD). METHODS: Active compounds and their potential targets were screened from the PubChem, TCMSP, NovoPro, and SwissTargetPrediction databases. Hypertension-related targets were retrieved from the OMIM and GeneCards databases, and overlapping targets were identified. The STRING database and Cytoscape 3.10.1 software were used to construct a protein-protein interaction network and a herb-component-target-disease network. Gene Ontology functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were performed to identify the key biological processes and signaling pathways involved. Using the CIBERSORT algorithm combined with correlation analysis, we investigated the association between key targets and immune cell infiltration. Molecular docking, molecular dynamics simulations, and ADMET predictions were performed to assess the binding stability and pharmacokinetic properties of the main compounds with their corresponding targets. Finally, the antihypertensive efficacy of ZLJYD was validated using a spontaneously hypertensive rat model, and alterations in gut microbiota were analyzed using 16S rDNA sequencing. RESULTS: A total of 123 active compounds and 267 hypertension-related targets of ZLJYD were identified. Enrichment analysis revealed that these targets were primarily associated with the PI3K-Akt signaling pathway and lipid and atherosclerosis pathways. Immune infiltration analysis suggested that the therapeutic effects of ZLJYD may involve the regulation of follicular helper T cells, naïve B cells, and naïve CD4⁺ T cells. Molecular docking and dynamics simulations supported the stable binding of key compounds to their target proteins, while ADMET predictions indicated favorable pharmacokinetic properties and safety profiles. Rat experiments demonstrated that ZLJYD significantly reduced blood pressure in spontaneously hypertensive rats, partially alleviated gut microbiota dysbiosis, and altered microbial community structure and phylogenetic diversity. CONCLUSION: This study systematically elucidates the potential mechanisms underlying the antihypertensive effects of ZLJYD through multiple components, targets, and pathways, particularly immune regulation and gut microbiota remodeling. These findings provide mechanistic insights into its potential therapeutic application.

16S rDNA sequencing↗
PubMed2004

In vivo and in vitro regulation of Akt activation in human endometrial cells is estrogen dependent.

Estrogen-bound estrogen receptors (ER) alpha and beta classically activate gene expression after binding to the estrogen response element in the promoter regions of target genes. Estrogen also has rapid, nongenomic effects. It activates several membranous or cytoplasmic kinase cascades, including the phosphatidylinositol 3-phosphate (PI3K/Akt) cascade, a signaling pathway that plays a key role in cell survival and apoptosis. Normal human endometrium is exposed to variable levels of steroid hormones throughout the menstrual cycle. We hypothesized that Akt phosphorylation in human endometrium may vary with the menstrual cycle and in early pregnancy and that fluctuations in estrogen level may play a role in Akt activation in endometrial cells. We analyzed Akt phosphorylation using in vivo and in vitro techniques, including Western blot, immunohistochemistry, and immunocytochemistry. Estradiol significantly increased Akt phosphorylation in endometrial cells. Rapid stimulation of Akt activation in cultured stromal cells was observed. Akt phosphorylation by estradiol was inhibited by the PI3K inhibitor, wortmannin, but not by the ER antagonist, ICI 182 780. The maximal effect on Akt activity was observed following 5-15 min of estradiol treatment. Our results suggest that estradiol may directly affect PI3K-related signaling pathway by increasing the phosphorylation of Akt in endometrial cells. Thus, estradiol may exert part of its proliferative and antiapoptotic effects by a nongenomic manner through the Akt signaling pathway.

Adenocarcinoma↗
PubMed2006

Potentiation of paclitaxel activity by the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin in human ovarian carcinoma cell lines with high levels of activated AKT.

Activation of the phosphatidylinositol-3-kinase (PI3K)/AKT survival pathway is a mechanism of cytotoxic drug resistance in ovarian cancer, and inhibitors of this pathway can sensitize to cytotoxic drugs. The HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) depletes some proteins involved in PI3K/AKT signaling, e.g., ERBB2, epidermal growth factor receptor (EGFR), and phosphorylated AKT (p-AKT). 17-AAG and paclitaxel were combined (at a fixed 1:1 ratio of their IC(50)) in four ovarian cancer cell lines that differ in expression of p-AKT, EGFR, and ERBB2. The EGFR-overexpressing A431 and KB epidermoid cell lines were also included. Combination indices (CI) were calculated using the median-effect equation and interpreted in the context of 17-AAG-mediated inhibition of PI3K signaling. Synergy was observed in IGROV-1- and ERBB2-overexpressing SKOV-3 ovarian cancer cells that express a high level of constitutively activated p-AKT [CI at fraction unaffected (fu)(0.5) = 0.50 and 0.53, respectively]. Slight synergy was observed in A431 cells (moderate p-AKT/overexpressed EGFR; CI at fu(0.5) = 0.76) and antagonism in CH1 (moderate p-AKT), HX62 cells (low p-AKT), and KB cells (low p-AKT/overexpressed EGFR; CI at fu(50) = 3.0, 3.5, and 2.0, respectively). The observed effects correlated with changes in the rate of apoptosis induction. 17-AAG induced a decrease in HSP90 client proteins (e.g., C-RAF, ERBB2, and p-AKT) or in downstream markers of their activity (e.g., phosphorylated extracellular signal-regulated kinase or p-AKT) in SKOV-3, IGROV-1, and CH1 cells at IC(50) concentrations. A non-growth-inhibitory concentration (6 nmol/L) reduced the phosphorylation of AKT (but not extracellular signal-regulated kinase) and sensitized SKOV-3 cells to paclitaxel. In conclusion, 17-AAG may sensitize a subset of ovarian cancer to paclitaxel, particularly those tumors in which resistance is driven by ERBB2 and/or p-AKT.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Astrocyte-derived transforming growth factor-{beta} mediates the neuroprotective effects of 17{beta}-estradiol: involvement of nonclassical genomic signaling pathways.

17beta-Estradiol (E2) and selective estrogen receptor modulators (SERMs), such as tamoxifen, mediate numerous effects in the brain, including neurosecretion, neuroprotection, and the induction of synaptic plasticity. Astrocytes, the most abundant cell type in the brain, influence many of these same functions and thus may represent a mediator of estrogen action. The present study examined the regulatory effect and underlying cell signaling mechanisms of E2-induced release of neurotropic growth factors from primary rat cortical astrocyte cultures. The results revealed that E2 (0.5, 1, and 10 nm) and tamoxifen (1 mum) increased both the expression and release of the neuroprotective cytokines, TGF-beta1 and TGF-beta2 (TGF-beta), from cortical astrocytes. The stimulatory effect of E2 was attenuated by the estrogen receptor (ER) antagonist, ICI182,780, suggesting ER dependency. The effect of E2 also appeared to involve mediation by the phosphotidylinositol 3-kinase (PI3K)/Akt signaling pathway, because E2 rapidly induced Akt phosphorylation, and pharmacological or molecular inhibition of the PI3K/Akt pathway prevented E2-induced release of TGF-beta. Additionally, the membrane-impermeant conjugate, E2-BSA, stimulated the release of TGF-beta, suggesting the potential involvement of a membrane-bound ER. Finally, E2, tamoxifen, and E2-BSA were shown to protect neuronal-astrocyte cocultures from camptothecin-induced neuronal cell death, effects that were attenuated by ICI182,780, Akt inhibition, or TGF-beta immunoneutralization. As a whole, these studies suggest that E2 induction of TGF-beta release from cortical astrocytes could provide a mechanism of neuroprotection, and that E2 stimulation of TGF-beta expression and release from astrocytes occurs via an ER-dependent mechanism involving mediation by the PI3K/Akt signaling pathway.

Animals↗
PubMed2002

Inhibition of FAK signaling activated by urokinase receptor induces dormancy in human carcinoma cells in vivo.

Activation of focal adhesion kinase (FAK), overexpressed in several human cancers, induces survival, proliferation and motility of cells in culture, but its functional importance in human tumor growth in vivo has not been elucidated. I explored the role of FAK in regulating tumorigenicity of human carcinoma cells, HEp3. These cells overexpress urokinase receptor (uPAR) which, by activating alpha5beta1 integrin, initiates an intracellular signal through FAK and Src leading to ERK activation and tumorigenicity in vivo. Down regulation of uPAR in these cells led to an approximately 3-5-fold reduction in FAK phosphorylation and association with Src and dormancy in vivo. Both FAK phosphorylation and ability to grow in vivo were restored by re-expression of uPAR. The FAK signaling pathway in T-HEp3 cells, measured by FAK phosphorylation, GTP-loaded Ras and ERK activation, was inhibited by transient or stable transfection of FAK related non-kinase (FRNK), known to have a dominant negative function, but not by a FRNK mutant version (S1034-FRNK). Most importantly, while vector- and mutant-S1034-FRNK transfected cells inoculated onto chicken embryo CAMs formed progressively growing tumors, the HA-FRNK-expressing T-HEp3 cells did not proliferate in vivo and remained dormant for at least 6 weeks. Both cell types had similar rate of apoptosis in vivo and the p38(SAPK) or PI3K-Akt signaling pathways were unaffected by FRNK. FRNK induced dormancy could be reverted by expression of an active-R4F-Mek1 mutant. These results show that active FAK is an important mediator of uPAR-regulated tumorigenicity of HEp3 cells and that interruption of FAK mitogenic signaling either through down-regulation of uPAR or by expression of FRNK can force human carcinoma cells into dormancy.

Carcinoma↗
PubMed1999

PTEN suppresses breast cancer cell growth by phosphatase activity-dependent G1 arrest followed by cell death.

PTEN/MMAC1/TEP1, a tumor suppressor gene, is frequently mutated in a variety of human cancers. Germ-line mutations of phosphatase and tensin homolog, deleted on chromosome ten (PTEN) are found in two inherited hamartoma tumor syndromes: Cowden syndrome, which has a high risk of breast, thyroid, and other cancers; and Bannayan-Zonana syndrome, a related disorder. PTEN encodes a phosphatase that recognizes both protein substrates and phosphatidylinositol-3,4,5-triphosphate. The lipid phosphatase activity of PTEN seems to be important for growth suppression through inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. We established clones with stable PTEN expression controlled by a tetracycline-inducible system to examine the consequences of increased levels of wild-type and mutant PTEN expression in a well-characterized breast cancer line, MCF-7. When we overexpressed PTEN in MCF-7, growth suppression was observed, but only if PTEN phosphatase activity is preserved. The initial growth suppression was attributable to G1 cell cycle arrest, whereas subsequent growth suppression was attributable to a combination of G1 arrest and cell death. Of note, the decrease in Akt phosphorylation preceded the onset-of suppression of cell growth. Treatment of MCF-7 cells with wortmannin, a PI3K inhibitor, caused cell growth inhibition in a way similar to the effects of overexpression of PTEN in this cell. In general, the inverse correlation between PTEN protein level and Akt phosphorylation was found in a panel of breast cancer cell lines. Therefore, PTEN appears to suppress breast cancer growth through down-regulating PI3K signaling, which leads to the blockage of cell cycle progression and the induction of cell death, in a sequential manner.

Androstadienes↗
PubMed2004

Sphingosine kinase activation regulates hepatocyte growth factor induced migration of endothelial cells.

Hepatocyte growth factor (HGF)-induced migration of endothelial cells is critical for angiogenesis. Sphingosine kinase (SPK) is a key enzyme catalyzing the formation of sphingosine-1-phosphate (S1P), a lipid messenger that is implicated in the regulation of a wide variety of important cellular events through both intracellular and extracellular mechanisms. The aim of this study was to investigate whether activation of SPK is involved in the migration of endothelial cells induced by HGF. The biological functions of HGF are mediated through the activation of its high-affinity tyrosine kinase receptor, c-met protooncogene. In the present study, Treatment of ECV304 endothelial cells with HGF resulted in tyrosine phosphorylation of c-Met and activation of SPK in a concentration-dependent manner. Either Ly294002 or PD98059, specific inhibitor of the PI3K and ERK/MAPK pathways, respectively, blocked the HGF-induced activation of SPK. HGF stimulation significantly increased intracellular S1P level, but no detectable secretion of S1P into the cell culture medium was observed. Treatment of ECV304 cells with pertussis toxin (PTX) has no effect on the HGF-induced migration, indicating extracellular S1P is dispensable for this process. Overexpression of wild-type SPK gene in ECV 304 cells increased the intracellular S1P and enhanced the HGF-induced migration, whereas inhibition of cellular SPK activity by N,N-dimethylsphingosine (DMS), a potent inhibitor of SPK, or by expression of a dominant-negative SPK (DN-SK) blocked the HGF-induced migration of ECV 304 cells. It is suggested that PI3K and ERK/MAPK mediated the activation of SPK and would be involved in the HGF-induced migration of endothelial cells. These results elucidate a novel mechanism by which intracellularly generated S1P mediates signaling from HGF/c-Met to the endothelial cell migration.

Cell Line↗
PubMed2005

HIV protease inhibitors block Akt signaling and radiosensitize tumor cells both in vitro and in vivo.

In tumor cells with mutations in epidermal growth factor receptor (SQ20B), H-Ras (T24), or K-Ras (MIAPACA2 and A549), the inhibition of Akt phosphorylation increases radiation sensitivity in clonogenic assays, suggesting that Akt is a potential molecular target when combined with therapeutic radiation. Insulin resistance and diabetes are recognized side effects of HIV protease inhibitors (HPIs), suggesting that these agents may inhibit Akt signaling. Because activation of the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway is common in human cancers, we hypothesized that HPIs can inhibit Akt activity resulting in increased tumor cell sensitivity to ionizing radiation-induced cell death. Five first-generation HPIs were subsequently tested and three of the five (amprenavir, nelfinavir, and saquinavir but not ritonavir or indinavir) inhibited Akt phosphorylation at Ser473 at serum concentrations routinely achieved in HIV patients. In both tumor cell colony formation assays and tumor regrowth delay experiments, combinations of drug and radiation exerted synergistic effects compared with either modality alone. In addition, in vivo, doses of amprenavir or nelfinavir comparable with the therapeutic levels achieved in HIV patients were sufficient to down-regulate phosphorylation of Akt in SQ20B and T24 xenografts. Finally, overexpression of active PI3K in cells without activation of Akt resulted in radiation resistance that could be inhibited with HPIs. Because there is abundant safety data on HPIs accumulated in thousands of HIV patients over the last 5 years, these agents are excellent candidates to be tested as radiation sensitizers in clinical trials.

Animals↗
PubMed2003

Growth and molecular profile of lung cancer cells expressing ectopic LKB1: down-regulation of the phosphatidylinositol 3'-phosphate kinase/PTEN pathway.

Germ-line mutations in LKB1 gene cause the Peutz-Jeghers syndrome (PJS), a genetic disease with increased risk of malignancies. Recently, LKB1-inactivating mutations have been identified in one-third of sporadic lung adenocarcinomas, indicating that LKB1 gene inactivation is critical in tumors other than those of the PJS syndrome. However, the in vivo substrates of LKB1 and its role in cancer development have not been completely elucidated. Here we show that overexpression of wild-type LKB1 protein in A549 lung adenocarcinomas cells leads to cell-growth suppression. To examine changes in gene expression profiles subsequent to exogenous wild-type LKB1 in A549 cells, we used cDNA microarrays. We detected deregulation of 100 genes involved in cell proliferation, apoptosis, and cell adhesion. Strikingly, modification of the expression of well-known p53-responsive genes such as GADD45, TOP2A, and p21 suggests that growth suppression in A549 cells overexpressing LKB1 may be mediated by p53. In addition, PTEN up-regulation indicates that LKB1 could be involved in the PTEN/phosphatidylinositol-3'-kinase(PI3K)/AKT molecular pathway. Thus, our results give some insights into the understanding of how LKB1 inactivation contributes to lung carcinogenesis.

AMP-Activated Protein Kinase Kinases↗
PubMed2026

Flavones in osteosarcoma: Molecular mechanisms, antitumor activity, and translational challenges.

Osteosarcoma remains the most common primary malignant bone tumor, and survival has improved little over recent decades because of metastasis and therapeutic resistance. Flavones exhibit diverse anti-osteosarcoma activities by suppressing proliferation, inducing apoptosis, ferroptosis and autophagy, inhibiting metastasis, and modulating oncogenic signaling pathways, including PI3K-Akt, Wnt-β-catenin, STAT3, MAPK, and NF-κB. This review summarizes the cell-line-specific molecular mechanisms of representative flavones, critically evaluates current experimental limitations, and discusses strategies to improve clinical translation through nanotechnology-based delivery and combination therapy. Although clinical evidence remains lacking, flavones represent promising adjunctive candidates for overcoming chemoresistance and improving osteosarcoma treatment.

apoptosis and metastasis↗
PubMed2004

Epidermal growth factor stimulation of RPE cell survival: contribution of phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways.

Epidermal growth factor (EGF) previously has been shown to stimulate short-term survival in vitro of cells derived from the native amphibian retinal pigment epithelium (RPE). In the present experiments, we have examined intracellular signaling pathways responsible for mediating these survival-specific growth factor effects, distinct from proliferative effects, using the human epithelial cell line RPE D407. When maintained as single cells in suspension culture in the absence of serum and exogenous survival factors, RPE D407 cell viability gradually declined over a 3-4 day period as a result of apoptotic cell death, a pattern similar to that seen for eye-derived RPE cells. Exposure to EGF (50 ng ml(-1)) enhanced cell survival by nearly 40% and caused a parallel increase in the tyrosine phosphate content of the EGF receptor (EGFR), as determined by immunoprecipitation and Western blotting. Both effects were completely blocked by 1 microm AG1478, an EGFR-selective tyrosine kinase inhibitor. EGF also stimulated phosphorylation of the phosphatidylinositol 3'-kinase (PI3K)-dependent effector kinase Akt, as well as that of the MEK-dependent mitogen-activated kinase (MAPK), extracellular signal-regulated kinase (ERK). Furthermore, EGF-induced protection was substantially reduced by either the PI3K inhibitor LY294002 (25 microm) or the MEK inhibitor U0126 (10 microm), under conditions in which phosphorylation of Akt and ERK1/2, respectively, was blocked. Our results indicate that EGF-stimulated survival of RPE D407 cells takes place as a result of signaling through both PI3K and ERK/MAPK pathways. Further, residual anti-apoptotic activity stimulated by EGF in the presence of both blockers suggests that additional as yet unidentified growth factor-dependent survival pathways exist.

Analysis of Variance↗
PubMed2002

Functional analysis of aortic endothelial cells expressing mutant PDGF receptors with respect to expression of matrix metalloproteinase-3.

Platelet-derived growth factor (PDGF) stimulates expression of matrix metalloproteinases (MMPs), including stromelysin-1 (MMP-3). Induction of these expressions is known to occur during the course of atherosclerosis, tumor invasion, and metastasis. We investigated PDGF-alpha receptor (alphaR)- and beta receptor (betaR)-mediated signaling pathways for the expression of MMP-3 and invasion activity using porcine aortic endothelial (PAE) cells with stable expression of normal or mutated PDGF receptors. RT-PCR and Western blot analyses revealed that PDGF-BB induces MMP-3 expression in PAE cells that exclusively express either the PDGF-alphaR or the -betaR, but not in non-transfected control cells. To identify the signals necessary for PDGF receptor-mediated induction of MMP-3 expression, several lines of PAE cells expressing mutant PDGF receptors were further analyzed. Cells expressing mutant PDGF receptors unable to associate with Src or PLCgamma, retained the ability to induce MMP-3 expression as a result of PDGF-BB stimulation. However, incubation with PDGF-BB did not induce MMP-3 expression in cells expressing a mutant PDGF-betaR unable to associate with phosphatidylinositol 3(')-kinase (PI3K). LY294002, a PI3K inhibitor, reduced PDGF-BB-stimulated MMP-3 expression in PAE cells expressing wild-type PDGF receptors. In contrast, PDGF-BB induced MMP-3 expression in the presence of U-73122, a PLCgamma inhibitor. Moreover, PDGF-BB enhanced the invasiveness of cells expressing wild type PDGF-beta receptors, but not of cells expressing mutant PDGF-betaRs impaired in their ability to associate with PI3K. In light of these results, it appears that PDGF-BB is capable of inducing MMP-3 expression through both the PDGF-alphaR and the -betaR, and the effects are contributed by the PI3K-mediated transduction pathways.

Animals↗
PubMed2003

Glucagon-like peptide-1 inhibits apoptosis of insulin-secreting cells via a cyclic 5'-adenosine monophosphate-dependent protein kinase A- and a phosphatidylinositol 3-kinase-dependent pathway.

The activation of the glucagon-like peptide-1 (GLP-1) receptor has been shown to have an important role in the functional activity of islet beta-cells and in the expansion of the islet cell mass. Constant remodeling of islet cell mass is mediated in vivo by proliferative and apoptotic stimuli to ensure a dynamic response to a changing demand for insulin. The present study was undertaken to investigate the biological activity of GLP-1 when cells were challenged by a proapoptotic stimulus. We have shown that activation of the GLP-1 receptor inhibits H(2)O(2)-induced apoptosis in a cultured mouse insulinoma cell line, termed MIN6. GLP-1 reduced DNA fragmentation and improved cell survival. This was mediated by an increased expression of the antiapoptotic proteins Bcl-2 and Bcl-xL. GLP-1 also prevented the H(2)O(2)-dependent cleavage of poly-(ADP-ribose)-polymerase. Inhibition of the GLP-1-dependent increase of cAMP by Rp-cAMP blocked the antiapoptotic action of GLP-1, as determined by DNA fragmentation and poly-(ADP-ribose)-polymerase assays and by detection of Bcl-2 and Bcl-xL protein levels. Investigation of the role of the protein kinases, PI-3 kinase (PI3K) and MAPK, by use of the inhibitors PD098059 and LY294002 demonstrated that the activation of PI3K, but not MAPK, was required to prevent proapoptotic events in cells exposed to H(2)O(2). The present study provides evidence that GLP-1 has an antiapoptotic action mediated by a cAMP- and PI3K-dependent signaling pathway.

Animals↗
PubMed2025

The impact of m6A methyltransferase METTL3 on airway remodeling in bronchial asthma.

BACKGROUND: Methyltransferase-like 3 (METTL3) is known to play a role in asthma airway remodeling and cell proliferation. Adenylate kinase 4 (AK4) regulates the proliferation of pulmonary artery smooth muscle cells and exerts its effects through the protein kinase B (AKT) pathway. However, the role of METTL3 and AK4-AKT in bronchial smooth muscle cells remains unclear. METHODS: Systemic METTL3 knockout mice and a mouse model of asthma were established. Airway remodeling was assessed using pulmonary function tests, histopathological staining, and Western blot analysis. RNA sequencing (RNA-seq) was performed to detect changes in gene expression following METTL3 knockdown. The 5-ethynyl-2'-deoxyuridine (EdU) assay was used to evaluate cell proliferation. Finally, the expression levels of relevant proteins were validated by Western blotting. RESULTS: Compared with the control model group, the METTL3 knockout group showed significantly reduced inflammatory cell infiltration, decreased collagen fiber deposition, and attenuated airway smooth muscle hyperplasia. RNA-seq revealed that the expression of numerous proliferation-related genes, including AK4, was upregulated following METTL3 knockdown. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that these genes were primarily enriched in the phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway. The EdU assay demonstrated that METTL3 knockdown inhibited cell proliferation. Western blot validation showed increased AK4 expression in lung tissues of the METTL3 knockout group compared to the control group, while phosphorylated AKT (p-AKT) levels were reduced. CONCLUSIONS: METTL3 knockout inhibits airway smooth muscle hyperplasia and alleviates airway remodeling in asthma. This effect may be mediated through the regulation of AK4 and the AKT signaling pathway.

Airway Remodeling↗
PubMed2003

The lethal effects of pharmacological cyclin-dependent kinase inhibitors in human leukemia cells proceed through a phosphatidylinositol 3-kinase/Akt-dependent process.

The impact of disruption of the PI3K (phosphatidylinositol 3-kinase) pathway on the response of human leukemia cells to pharmacological cyclin-dependent kinase (CDK) inhibitors has been examined. Exposure of U937 monocytic leukemia cells to minimally toxic concentrations of flavopiridol (FP), roscovitine, or CGP74514A for 3 h in conjunction with the PI3K inhibitor LY294002 (abbreviated LY in the article) resulted in a marked decrease in Akt phosphorylation. Coexposure of cells to LY and CDK inhibitors also resulted in an early (i.e., within 3 h) and striking increase in mitochondrial damage [e.g., cytochrome c, second mitochondria-derived activator of caspases/direct inhibitor of apoptosis (IAP)-binding protein with low isoelectric point (Smac/DIABLO), and apoptosis-initiating factor (AIF) release], caspase activation, and apoptosis. Similar interactions were observed in a variety of other leukemia cell types (e.g., HL-60, Jurkat, Raji, and NB4). Apoptosis, induced by FP/LY, was substantially blocked by ectopic expression of Bcl-2, but to a considerably lesser extent by dominant-negative caspase-8. FP-induced apoptosis was not enhanced by agents that inhibited protein kinase (PK) A (H89), PKC (GFX), mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK1/2; U0126), p38 MAP kinase (MAPK; SB202190), m-target of rapamycin (TOR; rapamycin), or ataxia-telangiectasia mutation (ATM; caffeine), whereas the PI3K inhibitor wortmannin exerted effects similar to those of LY. The dramatic potentiation of CDK inhibitor-induced apoptosis by LY was accompanied by diminished Bad phosphorylation, induction of Bcl-2 cleavage, and down-regulation of X-linked IAP (XIAP) and Mcl-1. Cells exposed to CDK inhibitors + LY also exhibited reduced phosphorylation of glycogen synthase kinase (GSK)-3, forkhead transcription factor (FKHR), p70(S6K), and ERK, but increased activation of p34(cdc2) and p38 MAPK. LY/CDK inhibitor-treated cells also displayed diminished pRb dephosphorylation on CDK2- and CDK4-specific sites, retinoblastoma protein cleavage, and down-regulation of cyclin D(1). Inducible expression of constitutively active (myristolated) Akt significantly, albeit partially, attenuated apoptosis in Jurkat leukemia cells treated with either FP alone or the combination of FP and LY. Finally, cotreatment with LY and FP resulted in a dramatic increase in apoptosis in primary leukemic blasts obtained from a patient with acute myeloblastic leukemia. Together, these findings suggest that the PI3K/Akt pathway plays a major role in regulating the apoptotic response of human leukemia cells to pharmacological CDK inhibitors and raise the possibility that combined interruption of CDK- and PI3K-related pathways may represent a novel therapeutic strategy in hematological malignancies.

2-Aminopurine↗
PubMed2005

Amiloride augments TRAIL-induced apoptotic death by inhibiting phosphorylation of kinases and phosphatases associated with the P13K-Akt pathway.

We have previously shown that low extracellular pH (pHe) promotes cell killing by the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In this study, we examined whether amiloride, an inhibitor of the Na(+)/H(+) antiporter capable of lowering the intracellular pH (pHi), can potentiate TRAIL-induced apoptotic death. Human prostate adenocarcinoma DU-145 cells were treated with various concentrations of TRAIL (10-200 ng/ml) and/or amiloride (0.1-1 mM) for 4 h. Amiloride, which caused little or no cytotoxicity by itself, enhanced TRAIL-induced apoptosis. The TRAIL-mediated activation of caspase, and PARP (poly (ADP-ribose) polymerase) cleavage were both promoted by amiloride. Western blot analysis showed that combined treatment with TRAIL and amiloride did not change the levels of TRAIL receptors (death receptor (DR)4, DR5, and DcR2 (decoy recepter 2) or antiapoptotic proteins (FLICE-inhibitory protein (FLIP), inhibitor of apoptosis (IAP), and Bcl-2). However, unlike pHe, amiloride promoted the dephosphorylation of Akt. Interestingly, amiloride also induced the dephosphorylation of P13K (phosphatidylinositol 3-kinase) and PDK-1 (phosphoinositide-dependent kinase-1) kinases along with PTEN (phosphatase and tensin homolog deleted on chromosome 10) and PP1alpha phosphatases. In vitro kinase assays revealed that amiloride inhibited phosphorylation of kinases and phosphatases by competing with ATP. Taken together, the present studies suggest that amiloride enhances TRAIL-induced cytotoxicity by inhibiting phosphorylation of the PI3K-Akt pathway-associated kinases and phosphatases.

Adenocarcinoma↗
PubMed2026

Elucidating the mechanism of Buyang Huanwu Decoction in the treatment of ischemic stroke: A network pharmacology and molecular docking study.

A large number of functional disorders and uncomfortable symptoms often remain following ischemic stroke (IS). Existing drug therapy is not ideal for the direct improvement of symptoms, which often leads to poor patient compliance with physical rehabilitation therapy. Buyang Huanwu Decoction (BYHWD) is a famous prescription that is effective in treating IS, especially during the sequela stage of IS. We analyzed the therapeutic mechanism of BYHWD through network pharmacology. This study aims to investigate the potential active ingredients, targets, and signaling pathways of BYHWD for the treatment of IS, utilizing network pharmacology and molecular docking technology. The active ingredients of 7 Chinese herbs in BYHWD were obtained from the Traditional Chinese Medicine Systems Pharmacology and HERB databases, and IS-related disease targets were searched in the DisGeNET, GeneCards, and OMIM databases. The protein-protein interaction network was constructed using the STRING database and analyzed by Cytoscape 3.10.2 software. Additionally, the target genes were uploaded to the Database for Annotation, Visualization, and Integrated Discovery website for Gene Ontology alongside Kyoto Encyclopedia of Genes and Genomes analyses. With the assistance of AutoDockTools and PyMOL software (Schrödinger, Inc.), a validation of molecular docking results and a visualization of the results were performed. The results showed that there were 190 intersection targets between the active drug components and IS, corresponding to 61 active components, among which the top 5 target genes were tumor suppressor protein 53, Jun proto-oncogene, AKT serine/threonine kinase 1, mitogen-activated protein kinase 1, and estrogen receptor alpha. The PI3K-Akt signaling pathway is one of the top 10 pathways. The molecular docking results indicated that most of the top 5 targets had good affinities for the 8 core compounds. This computational analysis suggests that BYHWD may treat IS through multiple targets and pathways. It may play a neuroprotective role by regulating the inflammatory response, oxidative stress, apoptosis, autophagy, and vascular endothelial homeostasis. The identification of core effective components provides a theoretical foundation and candidate compounds for further investigation into new drugs for the treatment of sequelae after IS.

Drugs, Chinese Herbal↗