达沙替尼对人脐静脉内皮细胞的损伤与PI3K/Akt途径抑制有关

目的探索达沙替尼对人脐静脉内皮细胞(HUVEC)增殖、迁移和凋亡等生物学特性的影响,为完善其临床应用提供资料。方法实验分组:达沙替尼组(达沙替尼处理浓度为50 nmol/L)、LY294002组(PI3K抑制剂,处理浓度为20μmol/L)、联合处理组(达沙替尼处理浓度为50 nmol/L、LY294002处理浓度为20μmol/L)及溶媒对照组(DMSO浓度为0.1%)。CCK8法检测细胞活性,划痕法检测细胞迁移,流式细胞术检测细胞凋亡和细胞周期,Western blot检测Akt和p-Akt蛋白水平。结果达沙替尼(1~400 nmol/L)不仅抑制HUVEC增殖,而且诱导其凋亡、抑制其迁移、阻滞细胞周期G1-S期转化。随浓度的升高与处理时间的延长(50 nmol/L,24 h~96 h)达沙替尼对细胞增殖抑制作用和诱导凋亡作用明显,同时HUVEC的迁移能力随达沙替尼浓度(50~100 nmol/L)的升高而降低。达沙替尼和PI3K抑制剂LY294002两者单独处理时均具有细胞增殖抑制作用,两者均明显抑制Akt蛋白磷酸化水平;两者联合处理时虽然细胞增殖抑制作用增强,但对Akt蛋白磷酸化水平的影响与单独处理相比差异不明显。结论达沙替尼可通过PI3K/Akt通路促进HUVEC损伤,抑制HUVEC增殖和迁移,改变细胞形态,阻滞HUVEC G1-S期转化,诱导细胞凋亡。     

Melatonin suppresses acrolein-induced IL-8 production in human pulmonary fibroblasts

Cigarette smoke (CS) causes harmful alterations in the lungs and airway structures and functions that characterize chronic obstructive pulmonary disease (COPD). In addition to COPD, active cigarette smoking causes other respiratory diseases and diminishes health status. Furthermore, recent studies show that, α, β-unsaturated aldehyde acrolein in CS induces the production of interleukin (IL)-8, which is known to be related to bronchitis, rhinitis, pulmonary fibrosis, and asthma. In addition, lung and pulmonary fibroblasts secrete IL-8, which has a chemotactic effect on leukocytes, and which in turn, play a critical role in lung inflammation. On the other hand, melatonin regulates circadian rhythm homeostasis in humans and has many other effects, which include antioxidant and anti-inflammatory effects, as demonstrated by the reduced expressions of iNOS, IL-1β, and IL-6 and increased glutathione (GSH) and superoxide dismutase activities. In this study, we investigated whether melatonin suppresses acrolein-induced IL-8 secretion in human pulmonary fibroblasts (HPFs). It was found that acrolein-induced IL-8 production was accompanied by increased levels of phosphorylation of Akt and extracellular signal-regulated kinases (ERK1/2) in HPFs, and that melatonin suppressed IL-8 production in HPFs. These results suggest that melatonin suppresses acrolein-induced IL-8 production via ERK1/2 and phosphatidylinositol 3-kinase (PI3K)/Akt signal inhibition in HPFs.     

PI3K/Akt信号通路对肝癌细胞系HepG2中SP细胞的影响

[目的]探讨PI3K/Akt信号通路对肝癌细胞系HepG2中肿瘤干细胞比例及干细胞特性的影响.[方法]使用PI3K/Akt通路抑制剂处理HepG2细胞后,使用流式技术分析HepG2细胞系中的侧群（SP）细胞的变化.软琼脂克隆形成实验检测PI3K/Akt抑制剂对HepG2细胞中SP细胞和非SP细胞成克隆能力的影响.[结果]HepG2细胞中存在SP细胞,经过LY294002处理后,SP细胞比例下降.LY294002可以显著降低SP细胞的软琼脂成克隆能力,对非SP细胞的软琼脂成克隆能力影响不明显.[结论]HepG2细胞中的SP细胞具有干细胞特性,PI3K/Akt信号通路对HepG2细胞中SP细胞的维持起重要作用,抑制PI3K/Akt信号通路后HepG2细胞中的SP细胞比例明显减低,并能显著抑制SP细胞的增殖速度、软琼脂成克隆能力,增加SP细胞对化疗药物的敏感性,为更加深入地了解肝癌干细胞的特性以及探索针对肿瘤干细胞的治疗提供理论依据.     

Embryonic liver fordin is involved in glucose glycolysis of hepatic stellate cell by regulating PI3K/Akt signaling

AIMTo investigate the role of embryonic liver fordin (ELF) in liver fibrosis by regulating hepatic stellate cells (HSCs) glucose glycolysis.METHODSThe expression of ELF and the glucose glycolysis-related proteins were evaluated in activated HSCs. siRNA was used to silence ELF expression in activated HSCs in vitro and the subsequent changes in PI3K/Akt signaling and glucose glycolysis-related proteins were observed.RESULTSThe expression of ELF increased remarkably in HSCs of the fibrosis mouse model and HSCs that were cultured for 3 wk in vitro. Glucose glycolysis-related proteins showed an obvious increase in the activated HSCs, such as phosphofructokinase, platelet and glucose transporter 1. ELF-siRNA, which perfectly silenced the expression of ELF in activated HSCs, led to the induction of glucose glycolysis-related proteins and extracellular matrix (ECM) components. Moreover, pAkt, which is an important downstream factor in PI3K/Akt signaling, showed a significant change in response to the ELF silencing. The expression of glucose glycolysis-related proteins and ECM components decreased remarkably when the PI3K/Akt signaling was blocked by Ly294002 in the activated HSCs.CONCLUSIONELF is involved in HSC glucose glycolysis by regulating PI3K/Akt signaling.     

Dependence of Wilms tumor cells on signaling through insulin-like growth factor 1 in an orthotopic xenograft model targetable by specific receptor inhibition

We have previously demonstrated an increased DNA copy number and expression of IGF1R to be associated with poor outcome in Wilms tumors. We have now tested whether inhibiting this receptor may be a useful therapeutic strategy by using a panel of Wilms tumor cell lines. Both genetic and pharmacological targeting resulted in inhibition of downstream signaling through PI3 and MAP kinases, G(1) cell cycle arrest, and cell death, with drug efficacy dependent on the levels of phosphorylated IGF1R. These effects were further associated with specific gene expression signatures reflecting pathway inhibition, and conferred synergistic chemosensitisation to doxorubicin and topotecan. In the in vivo setting, s.c. xenografts of WiT49 cells resembled malignant rhabdoid tumors rather than Wilms tumors. Treatment with an IGF1R inhibitor (NVP-AEW541) showed no discernable antitumor activity and no downstream pathway inactivation. By contrast, Wilms tumor cells established orthotopically within the kidney were histologically accurate and exhibited significantly elevated insulin-like growth factor-mediated signaling, and growth was significantly reduced on treatment with NVP-AEW541 in parallel with signaling pathway ablation. As a result of the paracrine effects of enhanced IGF2 expression in Wilms tumor, this disease may be acutely dependent on signaling through the IGF1 receptor, and thus treatment strategies aimed at its inhibition may be useful in the clinic. Such efficacy may be missed if only standard ectopic models are considered as a result of an imperfect recapitulation of the specific tumor microenvironment.     

Melatonin prevents human pancreatic carcinoma cell PANC-1-induced human umbilical vein endothelial cell proliferation and migration by inhibiting vascular endothelial growth factor expression

Abstract: Melatonin is an important natural oncostatic agent, and our previous studies have found its inhibitory action on tumor angiogenesis, but the mechanism remains unclear. It is well known that vascular endothelial growth factor (VEGF) plays key roles in tumor angiogenesis and has become an important target for antitumor therapy. Pancreatic cancer is a representative of the most highly vascularized and angiogenic solid tumors, which responds poorly to chemotherapy and radiation. Thus, seeking new treatment strategies targeting which have anti‐angiogenic capability is urgent in clinical practice. In this study, a co‐culture system between human umbilical vein endothelial cells (HUVECs) and pancreatic carcinoma cells (PANC‐1) was used to investigate the direct effect of melatonin on the tumor angiogenesis and its possible action on VEGF expression. We found HUVECs exhibited an increased cell proliferation and cell migration when co‐cultured with PANC‐1 cells, but the process was prevented when melatonin added to the incubation medium. Melatonin at concentrations of 1 μm and 1 mm inhibited the cell proliferation and migration of HUVECs and also decreased both the VEGF protein secreted to the cultured medium and the protein produced by the PANC‐1 cells. In addition, the VEGF mRNA expression was also down‐regulated by melatonin. Taken together, our present study shows that melatonin at pharmacological concentrations inhibited the elevated cell proliferation and cell migration of HUVECs stimulated by co‐culturing them with PANC‐1 cells; this was associated with a suppression of VEGF expression in PANC‐1 cells.     

Activated protein C ligation of ApoER2 (LRP8) causes Dab1-dependent signaling in U937 cells

Binding of activated protein C (APC) to cells triggers multiple beneficial cytoprotective activities that suppress apoptosis, inflammation, and endothelial barrier breakdown. One paradigm for APC''s signaling emphasizes its binding to endothelial cell protein C receptor (EPCR) and subsequent protease activated receptor (PAR)-1 activation. Here we used human monocytic-like U937 cells to evaluate apolipoprotein E receptor 2 (ApoER2)-dependent signaling by APC and found that APC initiated rapid phosphorylation of Tyr-220 in the adaptor protein disabled-1 (Dab1) and of Ser-473 in Akt. APC also induced phosphorylation of Ser-9 in glycogen synthase kinase 3β (GSK3β), which was blocked by the PI3K inhibitor {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. Receptor-associated protein (RAP), a general antagonist for binding of ligands to LDL receptor family members, inhibited APC-induced phosphorylation of Dab1 and GSK3β, whereas anti-EPCR or anti-PAR1 blocking antibodies did not. Knocking down ApoER2 by using siRNA-ablated APC induced Dab1 phosphorylation, suggesting that RAP-sensitive APC-induced signaling requires ApoER2. In surface plasmon resonance equilibrium binding studies, APC bound with high affinity to soluble (s) ApoER2 (apparent K_d, ≈30 nM) but not to soluble very low density lipoprotein receptor. RAP blocked APC binding to sApoER2 but not to sEPCR. RAP blocked binding of U937 cells to immobilized APC. RAP also blocked APC''s ability to inhibit endotoxin-induced tissue factor pro-coagulant activity of U937 cells. Thus, we propose that ligation of ApoER2 by APC signals via Dab1 phosphorylation and subsequent activation of PI3K and Akt and inactivation of GSK3β, thereby contributing to APC''s beneficial effects on cells.     

Sulforaphane induces inhibition of human umbilical vein endothelial cells proliferation by apoptosis

Sulforaphane (SUL), one of the isothiocyanates (ITCs), has recently been focused due to its inhibitory effects on tumor cell growth in vitro and in vivo, which is dependent on the direct effect on cancer cells. In the present study, we aimed to investigate the potential anti-angiogenic effect of SUL and its mechanism of action. Using the human umbilical vein endothelial cells (HUVECs) as a model of angiogenesis, we investigated the effect of SUL on the various steps of angiogenesis, including the proliferation of endothelial cells, tubular formation, and matrix metalloproteinase (MMP) production. Sulforaphane induced a dose-dependent decrease in the proliferative activity of endothelial cells, which was dependent on cell apoptosis. Also SUL inhibited tube formation on matrigel, but did not affect MMP production. The present results demonstrate the anti-angiogenic activity of SUL and its potential use as an anti-cancer drug is suggested.     

Cellular mechanisms involved in the melatonin inhibition of HT-29 human colon cancer cell proliferation in culture

The antiproliferative and proapoptotic properties of melatonin in human colon cancer cells in culture were recently reported. To address the mechanisms involved in these actions, HT-29 human colon cancer cells were cultured in RPMI 1640 medium supplemented with fetal bovine serum at 37 degrees C. Cell proliferation was assessed by the incorporation of [(3)H]-thymidine into DNA. Cyclic nucleotide levels, nitrite concentration, glutathione peroxidase and reductase activities, and glutathione levels were assessed after the incubation of these cells with the following drugs: melatonin membrane receptor agonists 2-iodo-melatonin, 2-iodo-N-butanoyl-5-methoxytryptamine, 5-methoxycarbonylamino-N-acetyltryptamine (GR-135,531), and the antagonists luzindole, 4-phenyl-2-propionamidotetralin, and prazosin; the melatonin nuclear receptor agonist CGP 52608, and four synthetic kynurenines analogs to melatonin 2-acetamide-4-(3-methoxyphenyl)-4-oxobutyric acid, 2-acetamide-4-(2-amino-5-methoxyphenyl)-4-oxobutyric acid, 2-butyramide-4-(3-methoxyphenyl)-4-oxobutyric acid and 2-butyramide-4-(2-amino-5-methoxyphenyl)-4-oxobutyric acid. The results show that the membrane receptors are not necessary for the antiproliferative effect of melatonin and the participation of the nuclear receptor in this effect is suggested. Moreover, the antioxidative and anti-inflammatory actions of melatonin, counteracting the oxidative status and reducing the production of nitric oxide by cultured HT-29 cells seem to be directly involved in the oncostatic properties of melatonin. Some of the synthetic kynurenines exert higher antiproliferative effects than melatonin. The results reinforce the clinical interest of melatonin due to the different mechanisms involved in its oncostatic role, and suggest a new synthetic pathway to obtain melatonin agonists with clinical applications to oncology.     

蛋白酶体抑制剂硼替佐米对胃癌SGC7901细胞的抗肿瘤作用及其机制

目的:研究蛋白酶体抑制剂硼替佐米对胃癌SGC7901细胞凋亡及细胞周期分布的影响,并进一步探讨其作用机制.方法:1-500 nmol/L的硼替佐米作用于人胃癌SGC7901细胞24-48 h,MTT法检测细胞存活率,流式细胞术PI染色检测细胞凋亡.Western blot检测多聚ADP-核糖聚合酶(PARP)和casp...     

FGF21 protects human umbilical vein endothelial cells against high glucose-induced apoptosis via PI3K/Akt/Fox3a signaling pathway

Aims

Diabetic macroangiopathy is the main cause of morbidity and mortality in patients with diabetes. Endothelial cell injury is a pathological precondition for diabetic macroangiopathy. Fibroblast growth factor 21 (FGF21) is a key metabolic regulator which has recently been suggested to protect cardiac myocytes and vascular cells against oxidative stress-induced injury in vitro and vivo. In this study, we aimed to investigate the protective capacity of FGF21 in human umbilical vein endothelial cells (HUVECs) against high glucose (HG)-induced apoptosis via phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt)/FoxO3a pathway.

醛固酮对人脐血管内皮细胞凋亡的作用

目的探讨醛固酮(ALD)对人脐静脉内皮细胞(HUVEC)凋亡的作用及其可能的机制。方法 HUVEC分成3大组:正常对照组、ALD处理组(10~(-7)、10~(-6)、10~(-5)mol/L ALD)及螺内酯(10~(-5)mol/L)处理组,流式细胞术检测HUVEC凋亡,免疫印迹法检测HUVEC盐皮质激素受体(MR)蛋白水平的表达。结果 (1)与对照组比较,10~(-7)～10~(-5)mol/L ALD处理后HUVEC凋亡增加。(2)10~(-7)～10~(-5)mol/L ALD诱导的HUVEC凋亡呈剂量依赖性。(3)10~(-6)、10~(-5)mol/L ALD组加入10~(-6)mol/L螺内酯处理后凋亡下降(P<0.01),即ALD诱导的HUVEC凋亡被螺内酯部分抑制。(4)ALD上调MR蛋白表达,螺内酯可部分阻断此作用。结论 ALD可能通过上调HUVEC的MR蛋白表达而诱导细胞凋亡。     

IGF-1对Rh1肉瘤细胞PI3K/Akt/mTOR信号通路的影响

目的 探讨胰岛素样生长因子(IGF)1对Rh1肉瘤细胞生长活性和PI3 K/Akt/mTOR信号通路的背景变化.方法 常规细胞培养,用无血清培养基消除内源性因子影响27h,再用IGF-1(终浓度为10 ng/ml)刺激72 h,流式细胞仪检测细胞生长活性;另外Western印迹方法观察IGF-1刺激细胞5、10、20、30和60min后Akt(s473)、S6的动态变化.结果 与对照组相比,IGF-1可促进Rh1细胞存活.IGF-1刺激不同时间后S6磷酸化则随着时间的延长逐渐增强;IGF-1亦导致Akt(s473)位点的磷酸化,随时间的延长,磷酸化Akt在5min时达高峰,此后逐渐减弱.结论 Akt、S6等是PI3K/Akt/mTOR信号通路中的重要信号分子,对Rhl细胞而言,在IGF-1刺激下S6有逐渐增强的变化,Akt (s473)位点磷酸化则有减弱的动态变化.     

Regulation of vascular endothelial growth factor by melatonin in human breast cancer cells

Melatonin exerts oncostatic effects on breast cancer by interfering with the estrogen‐signaling pathways. Melatonin reduces estrogen biosynthesis in human breast cancer cells, surrounding fibroblasts and peritumoral endothelial cells by regulating cytokines that influence tumor microenvironment. This hormone also exerts antiangiogenic activity in tumoral tissue. In this work, our objective was to study the role of melatonin on the regulation of the vascular endothelial growth factor (VEGF) in breast cancer cells. To accomplish this, we cocultured human breast cancer cells (MCF‐7) with human umbilical vein endothelial cells (HUVECs). VEGF added to the cultures stimulated the proliferation of HUVECs and melatonin (1 mm ) counteracted this effect. Melatonin reduced VEGF production and VEGF mRNA expression in MCF‐7 cells. MCF‐7 cells cocultured with HUVECs stimulated the endothelial cells proliferation and increased VEGF levels in the culture media. Melatonin counteracted both stimulatory effects on HUVECs proliferation and on VEGF protein levels in the coculture media. Conditioned media from MCF‐7 cells increased HUVECs proliferation, and this effect was significantly counteracted by anti‐VEGF and 1 mm melatonin. All these findings suggest that melatonin may play a role in the paracrine interactions between malignant epithelial cells and proximal endothelial cells through a downregulatory action on VEGF expression in human breast cancer cells, which decrease the levels of VEGF around endothelial cells. Lower levels of VEGF could be important in reducing the number of estrogen‐producing cells proximal to malignant cells as well as decreasing tumoral angiogenesis.     

Melatonin enhances alkaline phosphatase activity in differentiating human adult mesenchymal stem cells grown in osteogenic medium via MT2 melatonin receptors and the MEK/ERK (1/2) signaling cascade

The goals of this study were to determine (a) if melatonin enhances human adult mesenchymal stem cell (hAMSC) differentiation into osteoblasts as assessed by measuring alkaline phosphatase (ALP) enzyme activity, and (b) identify potential signal transduction pathways that mediate this process. ALP activity significantly increased in hAMSCs following a 10-day incubation in osteogenic medium, relative to hAMSCs incubated in basal growth medium alone. Melatonin (50 nm), added in combination with the osteogenic medium, significantly increased ALP activity relative to osteogenic medium alone. Co-exposure of hAMSCs to osteogenic medium supplemented with melatonin and either pertussis toxin or the melatonin receptor antagonists, luzindole or 4P-PDOT (MT2 receptor selective), inhibited the melatonin-induced increase in ALP activity, indicating the involvement of melatonin receptors, in particular, MT2 receptors. Assessment of melatonin receptor function following exposure to osteogenic medium containing either vehicle or melatonin produced dichotomous results. That is, if the differentiation of hAMSCs into an osteoblast was induced by osteogenic medium alone, then 2-[125I]-iodomelatonin binding and melatonin receptor function increased. However, examination of melatonin receptor function following chronic melatonin exposure, an exposure that resulted in a 50% enhancement in ALP activity, revealed that these receptors were desensitized. This was reflected by a complete loss in specific 2-[125I]-iodomelatonin binding as well as melatonin efficacy to inhibit forskolin-induced cAMP accumulation. Further characterization of the mechanisms underlying melatonin's effects on these differentiation processes revealed that MEK (1/2) and ERK (1/2), epidermal growth factor receptors, metalloproteinase and clathrin-mediated endocytosis were essential while PKA was not. Our results are consistent with a role for melatonin in osteoblast differentiation. If so, then, the decrease in plasma melatonin levels observed in humans during late adulthood may further enhance susceptibility to osteoporosis.