BACKGROUND: Drug resistance is the main cause of high mortality of lung cancer. This study was conducted to investigate the effect of folic acid (FA) on the resistance of non-small cell lung cancer (NSCLC) cells to Osimertinib (OSM) by regulating the methylation of dual specificity phosphatase 1 (DUSP1). METHODS: The OSM resistant NSCLC cell line PC9R was establishd by gradually escalation of OSM concentration in PC9 cells. PC9R cells were randomly grouped into Control group, OSM group (5 μmol/L OSM), FA group (600 nmol/L FA), methylation inhibitor decitabine (DAC) group (10 μmol/L DAC), FA+OSM group (600 nmol/L FA+5 μmol/L OSM), and FA+OSM+DAC group (600 nmol/L FA+5 μmol/L OSM+10 μmol/L DAC). CCK-8 method was applied to detect cell proliferation ability. Scratch test was applied to test the ability of cell migration. Transwell assay was applied to detect cell invasion ability. Flow cytometry was applied to measure and analyze the apoptosis rate of cells in each group. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) method was applied to detect the expression level of DUSP1 mRNA in cells. Methylation specific PCR (MSP) was applied to detect the methylation status of the DUSP1 promoter region in each group. Western blot was applied to analyze the expression levels of DUSP1 protein and key proteins in the DUSP1 downstream mitogen-activated protein kinase (MAPK) signaling pathway in each group. RESULTS: Compared with the Control group, the cell OD450 values (48 h, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of extracellular regulated protein kinases (ERK) were obviously increased (P<0.05); the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the DAC group were obviously increased (P<0.05); the apoptosis rate, the expression of p38 MAPK protein, the phosphorylation level of ERK, and the methylation level of DUSP1 were obviously reduced (P<0.05). Compared with the OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM group were obviously decreased (P<0.05); the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously increased (P<0.05). Compared with the FA+OSM group, the cell OD450 values (48, 72 h), scratch healing rate, number of cell invasions, and expression of DUSP1 in the FA+OSM+DAC group were obviously increased; the apoptosis rate, the methylation level of DUSP1, the expression of p38 MAPK protein, and the phosphorylation level of ERK were obviously reduced (P<0.05). CONCLUSIONS FA may inhibit DUSP1 expression by enhancing DUSP1 methylation, regulate downstream MAPK signal pathway, then promote apoptosis, inhibit cell invasion and metastasis, and ultimately reduce OSM resistance in NSCLC cells.
Humans ; Carcinoma, Non-Small-Cell Lung/genetics* ; Lung Neoplasms/genetics* ; Dual Specificity Phosphatase 1/pharmacology* ; Cell Proliferation ; p38 Mitogen-Activated Protein Kinases/pharmacology* ; Methylation ; Apoptosis ; Cell Line, Tumor

OBJECTIVE: To investigate the effect CD36 deficiency on muscle insulin signaling in mice fed a normal-fat diet and explore the possible mechanism. METHODS: Wild-type (WT) mice and systemic CD36 knockout (CD36^-/-) mice with normal feeding for 14 weeks (n=12) were subjected to insulin tolerance test (ITT) after intraperitoneal injection with insulin (1 U/kg). Real-time PCR was used to detect the mRNA expressions of insulin receptor (IR), insulin receptor substrate 1/2 (IRS1/2) and protein tyrosine phosphatase 1B (PTP1B), and Western blotting was performed to detect the protein expressions of AKT, IR, IRS1/2 and PTP1B in the muscle tissues of the mice. Tyrosine phosphorylation of IR and IRS1 and histone acetylation of PTP1B promoter in muscle tissues were detected using co-immunoprecipitation (Co-IP) and chromatin immunoprecipitation (ChIP), respectively. RESULTS: CD36^-/- mice showed significantly lowered insulin sensitivity with obviously decreased area under the insulin tolerance curve in comparison with the WT mice (P < 0.05). CD36^-/- mice also had significantly higher serum insulin concentration and HOMA-IR than WT mice (P < 0.05). Western blotting showed that the p-AKT/AKT ratio in the muscle tissues was significantly decreased in CD36^-/- mice as compared with the WT mice (P < 0.01). No significant differences were found in mRNA and protein levels of IR, IRS1 and IRS2 in the muscle tissues between WT and CD36^-/- mice (P>0.05). In the muscle tissue of CD36^-/- mice, tyrosine phosphorylation levels of IR and IRS1 were significantly decreased (P < 0.05), and the mRNA and protein levels of PTP1B (P < 0.05) and histone acetylation level of PTP1B promoters (P < 0.01) were significantly increased as compared with those in the WT mice. Intraperitoneal injection of claramine, a PTP1B inhibitor, effectively improved the impairment of insulin sensitivity in CD36^-/- mice. CONCLUSION CD36 is essential for maintaining muscle insulin sensitivity under physiological conditions, and CD36 gene deletion in mice causes impaired insulin sensitivity by up-regulating muscle PTP1B expression, which results in detyrosine phosphorylation of IR and IRS1.
Animals ; Gene Deletion ; Histones/genetics* ; Insulin ; Insulin Receptor Substrate Proteins/metabolism* ; Insulin Resistance/genetics* ; Membrane Cofactor Protein/genetics* ; Mice ; Mice, Knockout ; Muscles/metabolism* ; Phosphoric Monoester Hydrolases/metabolism* ; Protein Tyrosine Phosphatase, Non-Receptor Type 1/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; RNA, Messenger/metabolism* ; Receptor, Insulin/metabolism* ; Tyrosine/genetics* ; Up-Regulation

BACKGROUND: Dysregulation of hepatic glucose production (HGP) contributes to the development of type 2 diabetes mellitus. Telmisartan, an angiotensin II type 1 receptor blocker (ARB), has various ancillary effects in addition to common blood pressure-lowering effects. The effects and mechanism of telmisartan on HGP have not been fully elucidated and, therefore, we investigated these phenomena in hyperglycemic HepG2 cells and high-fat diet (HFD)-fed mice.METHODS: Glucose production and glucose uptake were measured in HepG2 cells. Expression levels of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase α (G6Pase-α), and phosphorylation levels of insulin receptor substrate-1 (IRS-1) and protein kinase C ζ (PKCζ) were assessed by western blot analysis. Animal studies were performed using HFD-fed mice.RESULTS: Telmisartan dose-dependently increased HGP, and PEPCK expression was minimally increased at a 40 μM concentration without a change in G6Pase-α expression. In contrast, telmisartan increased phosphorylation of IRS-1 at Ser302 (p-IRS-1-Ser302) and decreased p-IRS-1-Tyr632 dose-dependently. Telmisartan dose-dependently increased p-PKCζ-Thr410 which is known to reduce insulin action by inducing IRS-1 serine phosphorylation. Ectopic expression of dominant-negative PKCζ significantly attenuated telmisartan-induced HGP and p-IRS-1-Ser302 and -inhibited p-IRS-1-Tyr632. Among ARBs, including losartan and fimasartan, only telmisartan changed IRS-1 phosphorylation and pretreatment with GW9662, a specific and irreversible peroxisome proliferator-activated receptor γ (PPARγ) antagonist, did not alter this effect. Finally, in the livers from HFD-fed mice, telmisartan increased p-IRS-1-Ser302 and decreased p-IRS-1-Tyr632, which was accompanied by an increase in p-PKCζ-Thr410.CONCLUSION: These results suggest that telmisartan increases HGP by inducing p-PKCζ-Thr410 that increases p-IRS-1-Ser302 and decreases p-IRS-1-Tyr632 in a PPARγ-independent manner.
Animals ; Blotting, Western ; Diabetes Mellitus, Type 2 ; Diet, High-Fat ; Ectopic Gene Expression ; Glucose ; Glucose-6-Phosphatase ; Hep G2 Cells ; Insulin Receptor Substrate Proteins ; Insulin ; Liver ; Losartan ; Mice ; Peroxisomes ; Phosphoenolpyruvate ; Phosphorylation ; Protein Kinase C ; Protein Kinases ; Receptor, Angiotensin, Type 1 ; Receptor, Insulin ; Serine

Eleven flavonoids were isolated from the twigs of Broussonetia papyrifera by column chromatography over silica gel,ODS,MCI gel,and Sephadex LH-20,as well as RP-HPLC.Their structures were identified by spectroscopic methods including NMR,MS,UV,and IR as broupapyrin A(1),5,7,3',4'-tetrahydroxy-3-methoxy-8-geranylflavone(2),8-prenylquercetin-3-methyl ether(3),broussonol D(4),broussoflavonol B(5),uralenol(6),broussonol E(7),8-(1,1-dimethylallyl)-5'-(3-methylbut-2-enyl)-3',4',5,7-tetrahydroxyflanvonol(8),broussoflavonol E(9),4,2',4'-trihydroxychalcone(10),and butein(11).Compound 1 is a new isoprenylated flavonol.Compounds 3,6,10,and 11 were obtained from the genus Broussonetia for the first time,and 4 and 7 were firstly discovered in B.papyrifera.Compounds 1-5 and 7-9 showed significant inhibitory effects on PTP1 B with IC50 values ranging from(0.83±0.30) to(4.66±0.83) μmol·L-1.
Broussonetia ; chemistry ; Chromatography, High Pressure Liquid ; Flavonoids ; isolation & purification ; pharmacology ; Magnetic Resonance Spectroscopy ; Phytochemicals ; isolation & purification ; pharmacology ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; antagonists & inhibitors

Protein tyrosine phosphatase 1B (PTP1B) has led to an intense interest in developing its inhibitors as anti-diabetes, anti-obesity and anti-cancer agents. The fruits of Rubus chingii (Chinese raspberry) were used as a kind of dietary traditional Chinese medicine. The methanolic extract of R. chingii fruits exhibited significant PTP1B inhibitory activity. Further bioactivity-guided fractionation resulted in the isolation of three PTP1B inhibitory ursane-type triterpenes: ursolic acid (1), 2-oxopomolic acid (2), and 2α, 19α-dihydroxy-3-oxo-urs-12-en-28-oic acid (3). Kinetics analyses revealed that 1 was a non-competitive PTP1B inhibitor, and 2 and 3 were mixed type PTP1B inhibitors. Compounds 1-3 and structurally related triterpenes (4-8) were further analyzed the structure-activity relationship, and were evaluated the inhibitory selectivity against four homologous protein tyrosine phosphatases (TCPTP, VHR, SHP-1 and SHP-2). Molecular docking simulations were also carried out, and the result indicated that 1, 3-acetoxy-urs-12-ene-28-oic acid (5), and pomolic acid-3β-acetate (6) bound at the allosteric site including α3, α6, and α7 helix of PTP1B.
Enzyme Inhibitors ; chemistry ; metabolism ; Fruit ; chemistry ; Humans ; Kinetics ; Methanol ; chemistry ; Molecular Docking Simulation ; Molecular Structure ; Plant Extracts ; chemistry ; Protein Binding ; Protein Tyrosine Phosphatase, Non-Receptor Type 1 ; antagonists & inhibitors ; metabolism ; Protein Tyrosine Phosphatases ; antagonists & inhibitors ; Rubus ; chemistry ; Structure-Activity Relationship ; Triterpenes ; chemistry ; metabolism

BACKGROUND: Apart from its blood pressure-lowering effect by blocking the renin-angiotensin-aldosterone system, telmisartan, an angiotensin II type 1 receptor blocker (ARB), exhibits various ancillary effects including cardiovascular protective effects in vitro. Nonetheless, the protective effects of telmisartan in cerebrocardiovascular diseases are somewhat variable in large-scale clinical trials. Dysregulation of endothelial nitric oxide (NO) synthase (eNOS)-derived NO contributes to the developments of various vascular diseases. Nevertheless, the direct effects of telmisartan on endothelial functions including NO production and vessel relaxation, and its action mechanism have not been fully elucidated. Here, we investigated the mechanism by which telmisartan regulates NO production and vessel relaxation in vitro and in vivo. METHODS: We measured nitrite levels in culture medium and mouse serum, and performed inhibitor studies and western blot analyses using bovine aortic endothelial cells (BAECs) and a hyperglycemic mouse model. To assess vessel reactivity, we performed acetylcholine (ACh)-induced vessel relaxation assay on isolated rat aortas. RESULTS: Telmisartan decreased NO production in normoglycemic and hyperglycemic BAECs, which was accompanied by reduced phosphorylation of eNOS at Ser¹¹⁷⁹ (p-eNOS-Ser¹¹⁷⁹). Telmisartan increased the expression of protein phosphatase 2A catalytic subunit (PP2Ac) and co-treatment with okadaic acid completely restored telmisartan-inhibited NO production and p-eNOS-Ser¹¹⁷⁹ levels. Of the ARBs tested (including losartan and fimasartan), only telmisartan decreased NO production and p-eNOS-Ser¹¹⁷⁹ levels, and enhanced PP2Ac expression. Co-treatment with GW9662 had no effect on telmisartan-induced changes. In line with in vitro observations, telmisartan reduced serum nitrite and p-eNOS-Ser¹¹⁷⁹ levels, and increased PP2Ac expression in high fat diet-fed mice. Furthermore, telmisartan attenuated ACh-induced rat aorta relaxation. CONCLUSION: We demonstrated that telmisartan inhibited NO production and vessel relaxation at least in part by PP2A-mediated eNOS-Ser¹¹⁷⁹ dephosphorylation in a peroxisome proliferator-activated receptor γ-independent manner. These results may provide a mechanism that explains the inconsistent cerebrocardiovascular protective effects of telmisartan.
Acetylcholine ; Animals ; Aorta ; Blotting, Western ; Catalytic Domain ; Endothelial Cells ; In Vitro Techniques ; Losartan ; Mice ; Mice, Obese ; Nitric Oxide Synthase Type III ; Nitric Oxide ; Okadaic Acid ; Peroxisomes ; Phosphorylation ; Protein Phosphatase 2 ; Rats ; Receptor, Angiotensin, Type 1 ; Relaxation ; Renin-Angiotensin System ; Vascular Diseases

Laryngeal squamous cell carcinoma (LSCC) is the most common type of head and neck squamous cell carcinoma (HNSCC) worldwide. Protein phosphatase 2A (PP2A) dysfunction has been widely reported in a broad range of malignancies due to its distinctive role in miscellaneous cellular processes. However, it is poorly understood whether aberrant alterations of PP2A are involved in the network of oncogenic events in LSCC. Here, we detected a panel of PP2A-associated proteins using western blot in both laryngeal squamous cell carcinoma tissues and paired adjacent normal tissues from patients (Data S1). We found that phospho-PP2A/C (Y307), α4, cancerous inhibitor of protein phosphatase 2A (CIP2A), Akt, ezrin, phospho-ezrin (T567), 14-3-3, and focal adhesion kinase (FAK) showed increased expression levels in carcinoma tissues relative to normal tissues, while phospho-Akt (T308) showed decreased levels. Our study, thus, provides a rationale for targeting PP2A to develop novel therapies and proposes a combination of interrelated biomarkers for the diagnostic evaluation and prognosis prediction in LSCC.
Autoantigens/metabolism* ; Biomarkers, Tumor/metabolism* ; Carcinoma, Squamous Cell/metabolism* ; Case-Control Studies ; Cytoskeletal Proteins/metabolism* ; Focal Adhesion Kinase 1/metabolism* ; Gene Expression Profiling ; Gene Expression Regulation ; Gene Expression Regulation, Neoplastic ; Humans ; Intracellular Signaling Peptides and Proteins/metabolism* ; Laryngeal Neoplasms/metabolism* ; Larynx/metabolism* ; Membrane Proteins/metabolism* ; Phosphorylation ; Protein Phosphatase 2/metabolism*

Thyroid diseases, including autoimmune thyroid diseases and thyroid cancer, are known to have high heritability. Family and twin studies have indicated that genetics plays a major role in the development of thyroid diseases. Thyroid function, represented by thyroid stimulating hormone (TSH) and free thyroxine (T4), is also known to be partly genetically determined. Before the era of genome-wide association studies (GWAS), the ability to identify genes responsible for susceptibility to thyroid disease was limited. Over the past decade, GWAS have been used to identify genes involved in many complex diseases, including various phenotypes of the thyroid gland. In GWAS of autoimmune thyroid diseases, many susceptibility loci associated with autoimmunity (human leukocyte antigen [HLA], protein tyrosine phosphatase, non-receptor type 22 [PTPN22], cytotoxic T-lymphocyte associated protein 4 [CTLA4], and interleukin 2 receptor subunit alpha [IL2RA]) or thyroid-specific genes (thyroid stimulating hormone receptor [TSHR] and forkhead box E1 [FOXE1]) have been identified. Regarding thyroid function, many susceptibility loci for levels of TSH and free T4 have been identified through genome-wide analyses. In GWAS of differentiated thyroid cancer, associations at FOXE1, MAP3K12 binding inhibitory protein 1 (MBIP)-NK2 homeobox 1 (NKX2-1), disrupted in renal carcinoma 3 (DIRC3), neuregulin 1 (NRG1), and pecanex-like 2 (PCNXL2) have been commonly identified in people of European and Korean ancestry, and many other susceptibility loci have been found in specific populations. Through GWAS of various thyroid-related phenotypes, many susceptibility loci have been found, providing insights into the pathogenesis of thyroid diseases and disease co-clustering within families and individuals.
Autoimmunity ; Genes, Homeobox ; Genetics ; Genome-Wide Association Study* ; Graves Disease ; Hashimoto Disease ; Humans ; Leukocytes ; Neuregulin-1 ; Phenotype ; Protein Tyrosine Phosphatase, Non-Receptor Type 22 ; Receptors, Interleukin-2 ; T-Lymphocytes, Cytotoxic ; Thyroid Diseases* ; Thyroid Gland* ; Thyroid Neoplasms* ; Thyrotropin ; Thyroxine

Human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) are used in tissue repair and regeneration; however, the mechanisms involved are not well understood. We investigated the hair growth-promoting effects of hUCB-MSCs treatment to determine whether hUCB-MSCs enhance the promotion of hair growth. Furthermore, we attempted to identify the factors responsible for hair growth. The effects of hUCB-MSCs on hair growth were investigated in vivo, and hUCB-MSCs advanced anagen onset and hair follicle neogeneration. We found that hUCB-MSCs co-culture increased the viability and up-regulated hair induction-related proteins of human dermal papilla cells (hDPCs) in vitro. A growth factor antibody array revealed that secretory factors from hUCB-MSCs are related to hair growth. Insulin-like growth factor binding protein-1 (IGFBP-1) and vascular endothelial growth factor (VEGF) were increased in co-culture medium. Finally, we found that IGFBP-1, through the co-localization of an IGF-1 and IGFBP-1, had positive effects on cell viability; VEGF secretion; expression of alkaline phosphatase (ALP), CD133, and β-catenin; and formation of hDPCs 3D spheroids. Taken together, these data suggest that hUCB-MSCs promote hair growth via a paracrine mechanism.
Alkaline Phosphatase ; Alopecia ; Cell Survival ; Coculture Techniques ; Fetal Blood* ; Hair Follicle ; Hair* ; Humans* ; In Vitro Techniques ; Insulin-Like Growth Factor Binding Protein 1 ; Insulin-Like Growth Factor I ; Intercellular Signaling Peptides and Proteins* ; Mesenchymal Stromal Cells ; Regeneration ; Stem Cells* ; Umbilical Cord* ; Vascular Endothelial Growth Factor A

Background: Glucocorticoid (GC) is the first-line therapy for asthma, but some asthmatics are insensitive to it. Glucocorticoid-induced transcript 1 gene (GLCCI1) is reported to be associated with GCs efficiency in asthmatics, while its exact mechanism remains unknown. Methods: A total of 30 asthmatic patients received fluticasone propionate for 12 weeks. Forced expiratory volume in 1 s (FEV) and GLCCI1 expression were detected. Asthma model was constructed in wild-type and GLCCI1 knockout (GLCCI1) mice. Glucocorticoid receptor (GR) and mitogen-activated protein kinase phosphatase 1 (MKP-1) expression were detected by polymerase chain reaction and Western blotting (WB). The phosphorylation of p38 mitogen-activated protein kinase (MAPK) was also detected by WB. Results: In asthmatic patients, the change of FEV was well positively correlated with change of GLCCI1 expression (r = 0.430, P = 0.022). In animal experiment, GR and MKP-1 mRNA levels were significantly decreased in asthmatic mice than in control mice (wild-type: GR: 0.769 vs. 1.000, P = 0.022; MKP-1: 0.493 vs. 1.000, P < 0.001. GLCCI1: GR: 0.629 vs. 1.645, P < 0.001; MKP-1: 0.377 vs. 2.146, P < 0.001). Hydroprednisone treatment significantly increased GR and MKP-1 mRNA expression levels than in asthmatic groups; however, GLCCI1 asthmatic mice had less improvement (wild-type: GR: 1.517 vs. 0.769, P = 0.023; MKP-1: 1.036 vs. 0.493, P = 0.003. GLCCI1: GR: 0.846 vs. 0.629, P = 0.116; MKP-1: 0.475 vs. 0.377, P = 0.388). GLCCI1 asthmatic mice had more obvious phosphorylation of p38 MAPK than wild-type asthmatic mice (9.060 vs. 3.484, P < 0.001). It was still higher even though after hydroprednisone treatment (6.440 vs. 2.630, P < 0.001). Conclusions: GLCCI1 deficiency in asthmatic mice inhibits the activation of GR and MKP-1 and leads to more obvious phosphorylation of p38 MAPK, leading to a decremental sensitivity to GCs. Trial Registration ChiCTR.org.cn, ChiCTR-RCC-13003634; http://www.chictr.org.cn/showproj.aspx?proj=5926.
Animals ; Asthma ; drug therapy ; metabolism ; Dual Specificity Phosphatase 1 ; genetics ; metabolism ; Forced Expiratory Volume ; genetics ; physiology ; Glucocorticoids ; therapeutic use ; Mice ; Mice, Knockout ; Phosphorylation ; genetics ; physiology ; Receptors, Glucocorticoid ; deficiency ; genetics ; metabolism ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism