Inhibitory Effect of Liquiritigenin on Migration Via Downregulation ProMMP-2 and PI3K/Akt Signaling Pathway in Human Lung Adenocarcinoma A549 cells

Liquiritigenin (LQ) is a flavanone extracted from Glycyrrhizae, which has multiple biological effects, such as antiinflammation and anticancer. This study is the first to investigate the effect of LQ on the migration of human lung adenocarcinoma A549 cells in vitro. First, LQ exhibited inhibitory effects on the adhesion and migration of A549 cells in the absence of cytotoxicity. Gelatin zymography and Western blot analysis showed that LQ significantly reduced the expression of promatrix metalloproteinase-2 (proMMP-2) in A549 cells in terms of both activity and protein level. Second, LQ inhibited the phosphorylation of Akt and activated the phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2). Furthermore, the treatment of inhibitors specific for Akt (LY294002) and ERK1/2 (U0126) to A549 cells resulted in reduced activity of proMMP-2. These results suggested that the inhibition on proMMP-2 expression by LQ may be through suppression on PI3K/Akt signaling pathway, which in turn led to the inhibition of lung adenocarcinoma A549 cells migration. However, activation of ERK might not be involved in the regulation of proMMP-2. Taken together, LQ may be considered as a potential interfering agent of cancer progression.     

All-Trans Retinoic Acid Inhibits Human Colorectal Cancer Cells RKO Migration via Downregulating Myosin Light Chain Kinase Expression through MAPK Signaling Pathway

All-trans-retinoic acid (ATRA) inhibits the invasive and metastatic potentials of various cancer cells. However, the underlying mechanism is unclear. Here, we demonstrate that ATRA inhibited colorectal cancer cells RKO (human colon adenocarcinoma cell) migration by downregulating cell movement and increasing cell adhesion. ATRA inhibited the expression and activation of myosin light chain kinase (MLCK) in RKO cells, while the expression level of MLC phosphatase (MLCP) had no change in RKO cells treated with or without ATRA. The expression and activity of MLC was also inhibited in RKO cells exposed to ATRA. Intriguingly, ATRA increased the expression of occludin messenger RNA (mRNA) and protein and its localization on cell membrane. However, ATRA did not change the expression of zonula occludens 1 (ZO-1), but increased the accumulation of ZO-1 on RKO cells membrane. ML-7, an inhibitor of MLCK, significantly inhibited RKO cell migration. Furthermore, knockdown of endogenous MLCK expression inhibited RKO migration. Mechanistically, we showed that MAPK-specific inhibitor PD98059 enhanced the inhibitory effect of ATRA on RKO migration. In contrast, phorbol 12-myristate 13-acetate (PMA) attenuated the effects of ATRA in RKO cells. Moreover, knocking down endogenous extracellular signal-regulated kinase (ERK) expression inhibited MLCK expression in the RKO cells. In conclusion, ATRA inhibits RKO migration by reducing MLCK expression via extracellular signal-regulated kinase 1/Mitogen-activated protein kinase (ERK1/MAPK) signaling pathway.     

Fatty Acid Synthase Inhibition Induces Differential Expression of Genes Involved in Apoptosis and Cell Proliferation in Ocular Cancer Cells

Fatty acid synthase (FASN), a lipogenic multienzyme complex, is overexpressed in the ocular cancer, retinoblastoma, and is strongly correlated with tumor invasion. Dietary nutrients are reported to exert anticancer effects through inhibition of lipid metabolism. Differential gene expression in cultured retinoblastoma cells induced by cerulenin, a chemical inhibitor of FASN, was evaluated by cDNA microarray analysis. Cerulenin treatment resulted in significant upregulation of cytochrome c (CYCS) by 1.2-fold, whereas S-phase kinase-associated protein-2 (SKP2), a negative regulator of cell cycle, and the lipid metabolic genes (PPARA, RXRA, and ACACB) were significantly downregulated by ?1.59-, ?1.8-, ?1.83-, and ?1.5-fold, respectively, in comparison with untreated cancer cells. The expressions of key differentially expressed genes were confirmed by quantitative real-time PCR. The altered expression of genes involved in cell proliferation, cell signaling, apoptosis, and cell cycle, correlated with the anticancer effects of cerulenin. FASN inhibition may thus be a potential strategy in retinoblastoma management.     

Involvement of the PI3K/Akt/Nrf2 Signaling Pathway in Resveratrol-Mediated Reversal of Drug Resistance in HL-60/ADR Cells

Resistance to chemotherapy drugs, such as adriamycin (ADR), is a common problem in acute myeloid leukemia (AML) patients. We hypothesized that the natural compound resveratrol (Res) may reverse AML drug resistance through the PI3K/Akt/Nrf2 pathway. We investigated the in vitro effect of Res using human promyelocytic leukemia cells (HL-60) and the ADR-resistant cell line (HL-60/ADR) and treated with either Res or ADR?+?Res. Cellular proliferation inhibition rate, auto-fluorescence intensity of ADR in HL-60/ADR cells and HL-60 cells, mRNA expression of Nrf2 and the drug-resistant gene MRP1, and protein expression of PI3K, Akt, p-Akt, Nrf2, and MRP1 were measured. Results showed ADR?+?Res had a more significant inhibitory effect than ADR alone on HL-60/ADR cells. Auto-fluorescence intensity of ADR in HL-60/ADR cells treated with ADR?+?Res significantly increased. No difference of the auto-fluorescence intensity of ADR was observed in HL-60 cells treated with ADR and ADR?+?Res. mRNA expression of Nrf2 and MRP1 significantly decreased in HL-60/ADR cells treated with both Res and ADR?+?Res; protein expression of PI3K, p-Akt, Nrf2, and MRP1 significantly decreased in HL-60/ADR cells treated with PI3K inhibitor, Res and ADR?+?Res. In conclusion, Res reverses the drug resistance of AML HL-60/ADR cells through regulation of the PI3K/Akt/Nrf2 signaling pathway and MRP1 expression.     

Isoflavones Inhibit Proliferation of Ovarian Cancer Cells In Vitro Via an Estrogen Receptor-Dependent Pathway

Incidence rates of ovarian cancer remain lowest in Asian nations, which consume diets rich in soy products, whereas they remain among the highest in the United States and other Western nations, which consume low amounts of soy foods. The hypothesis of this study is that soy-derived isoflavones inhibit the proliferation of ovarian cancer cells in vitro by regulating cytokine synthesis. Cell proliferation was evaluated by bromodeoxyuridine and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. DNA synthesis of Caov-3 and NIH:OVCAR-3, two ovarian cancer cell lines, was significantly inhibited by genistein or daidzein at dietarily relevant concentrations (10^{- 8-}10^{- 10} M). Also, the number of viable cells was significantly lower (45-75%) in all isoflavone-treated groups than in the control group (P ? 0.01). The addition of ICI-182780, an estrogen antagonist, blocked these inhibitory effects. In addition, interleukin-6 synthesis by these two cell lines was inhibited by genistein or daidzein; production was decreased by ~20% compared with the control group (P ? 0.05). In contrast, transforming growth factor-β₁ production in ovarian cancer cells incubated with genistein or daidzein was significantly greater, i.e., by ~30%, than in the control group (P ? 0.05). Addition of ICI-182780 also neutralized the effects of isoflavones on the production of these two cytokines by ovarian cancer cells. In summary, genistein and daidzein independently modify cytokine production and reduce ovarian cancer cell proliferation via, at least in part, an estrogen receptor-dependent pathway.     

PI3K/Akt信号通路对胃癌细胞SGC7901细胞化疗效果的影响

目的运用磷脂酰肌醇3-激酶抑制剂(phosphatidylinositol 3-kinases,PI3-K)LY294002[2-(4-吗啉基)-8-苯基-4氢-1-苯并吡喃-4-酮]作用于胃癌细胞系SGC7901,探讨抑制PI3K/Akt信号转导通路对胃癌细胞化疗敏感性的影响。方法采用MTT比色法,流式细胞术检测5-FU、DDP及ADM单独或联合PI3K抑制剂LY294002对人胃癌细胞SGC7901的抑制率、凋亡率。并分析单独及联合应用LY294002对SGC7901细胞周期的影响。Western-blot检测单独及联合化疗药后P-Akt蛋白在SGC7901细胞中的表达水平。结果单独使用化疗药5-FU、DDP及ADM均可抑制SGC7901细胞增殖、诱导其凋亡。当化疗药与抑制剂联合应用,对细胞的抑制作用明显增强,促凋亡作用增强,与对照组比较(P0.05)。细胞周期同步分析显示,单独用药均可将SGC7901细胞阻滞于G0/G1期。联合使用抑制剂使处于G0/G1期细胞增加。Western blot显示化疗药上调P-Akt蛋白的表达,联合使用抑制剂后SGC7901细胞P-Akt蛋白的表达与未使用抑制剂比较减弱,差异有统计学意义(P0.05)。结论阻断PI3K/Akt信号通路可提高化疗药5-FU、DDP及ADM对胃癌细胞株SGC7901的抑制率,凋亡率并使阻滞于G0/G1期细胞增多;LY294002通过阻断PI3K/Akt信号通路,抑制P-Akt蛋白表达,增强化疗药的敏感性;LY294002阻断PI3K/Akt信号通路对5-FU、DDP、ADM治疗胃癌有一定的协同或增强作用。     

Long-Chain Omega-3 Polyunsaturated Fatty Acid Intake and Risk of Colorectal Cancer

Research suggests that long-chain omega-3 polyunsaturated fatty acids (LC-PUFAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have antineoplastic properties, yet evidence for association between LC-PUFAs and colorectal cancer (CRC) remains inconsistent. Using the VITamins And Lifestyle (VITAL) cohort, we evaluated how EPA/DHA intake, and its primary sources, fish oil supplement use and dark fish consumption, relate to CRC risk. A total of 68,109 Washington residents aged 50–76 completed a questionnaire between 2000–2002 and were followed for CRC through 2008 (n = 488). Persons using fish oil supplements on 4+ days/wk for 3+ yr experienced 49% lower CRC risk than nonusers (hazard ratio = 0.51, 95% CI = 0.26–1.00; P trend = 0.06). The association between fish oil use and decreased CRC risk was primarily observed for men (P interaction = 0.02; P trend men = 0.02; P trend women = 0.88) and for colon cancer (P difference = 0.05; P trend colon = 0.03; P trend rectum = 0.87). Although dark fish and total EPA + DHA intake were not associated with CRC risk overall, these associations varied by genetic risk (P interaction = 0.009 and 0.02, respectively), with inverse associations observed among low-moderate genetic risk groups and positive associations observed among high risk groups. Results suggest that associations between LC-PUFA intake and CRC may vary by gender, subsite, and genetic risk, providing additional insight into the potential role of LC-PUFAs in cancer prevention.     

PPAR-α通过PI3K/Akt/FoxO1信号通路的负性调控心肌细胞肥大

目的观察PPAR-α对心肌细胞肥大负性调控时,机体中PI3K/Akt/Fox O1信号通路的变化情况。方法实验小鼠以异丙肾上腺素诱导心肌细胞肥大,使用实时定量聚合酶链式反应检测Fox O1 m RNA、PPAR-α表达水平,同时应用Feno预处理后观察Fox O1 m RNA、PPAR-α表达水平变化。结果异丙肾上腺素诱导后,心肌细胞中的PPAR-αm RNA、Fox O1 m RNA水平降低。Feno能抑制心肌肥大细胞表面积增加,RNAi通过PPAR-αm RNA使心肌肥大细胞表面积增加,以PI3K抑制剂LY处理心肌细胞,Fox O1 m RNA表达增加。结论 PPAR-α对心肌细胞肥大负调控与PI3K/Akt通路抑制、增加Fox O1表达有关。     

Activation of PI3K/Akt Signaling Pathway in Rat Hypothalamus Induced by an Acute Oral Administration of D-Pinitol

D-Pinitol (DPIN) is a natural occurring inositol capable of activating the insulin pathway in peripheral tissues, whereas this has not been thoroughly studied in the central nervous system. The present study assessed the potential regulatory effects of DPIN on the hypothalamic insulin signaling pathway. To this end we investigated the Phosphatidylinositol-3-kinase (PI3K)/Protein Kinase B (Akt) signaling cascade in a rat model following oral administration of DPIN. The PI3K/Akt-associated proteins were quantified by Western blot in terms of phosphorylation and total expression. Results indicate that the acute administration of DPIN induced time-dependent phosphorylation of PI3K/Akt and its related substrates within the hypothalamus, indicating an activation of the insulin signaling pathway. This profile is consistent with DPIN as an insulin sensitizer since we also found a decrease in the circulating concentration of this hormone. Overall, the present study shows the pharmacological action of DPIN in the hypothalamus through the PI3K/Akt pathway when giving in fasted animals. These findings suggest that DPIN might be a candidate to treat brain insulin-resistance associated disorders by activating insulin response beyond the insulin receptor.     

Olive Mill Wastewater Inhibits Growth and Proliferation of Cisplatin- and Gemcitabine-Resistant Bladder Cancer Cells In Vitro by Down-Regulating the Akt/mTOR-Signaling Pathway

Bladder cancer patients whose tumors develop resistance to cisplatin-based chemotherapy often turn to natural, plant-derived products. Beneficial effects have been particularly ascribed to polyphenols, although their therapeutic relevance when resistance has developed is not clear. The present study evaluated the anti-tumor potential of polyphenol-rich olive mill wastewater (OMWW) on chemo-sensitive and cisplatin- and gemcitabine-resistant T24, RT112, and TCCSUP bladder cancer cells in vitro. The cells were treated with different dilutions of OMWW, and tumor growth and clone formation were evaluated. Possible mechanisms of action were investigated by evaluating cell cycle phases and cell cycle-regulating proteins. OMWW profoundly inhibited the growth and proliferation of chemo-sensitive as well as gemcitabine- and cisplatin-resistant bladder cancer cells. Depending on the cell line and on gemcitabine- or cisplatin-resistance, OMWW induced cell cycle arrest at different phases. These differing phase arrests were accompanied by differing alterations in the CDK-cyclin axis. Considerable suppression of the Akt-mTOR pathway by OMWW was observed in all three cell lines. Since OMWW blocks the cell cycle through the manipulation of the cyclin-CDK axis and the deactivation of Akt-mTOR signaling, OMWW could become relevant in supporting bladder cancer therapy.     

Mulberry Leaf and Neochlorogenic Acid Alleviates Glucolipotoxicity-Induced Oxidative Stress and Inhibits Proliferation/Migration via Downregulating Ras and FAK Signaling Pathway in Vascular Smooth Muscle Cell

Mulberry leaf (Morus alba L.) has been used as a health food and in traditional medicine to treat several metabolic diseases, including diabetes, hypertension, and hyperlipidemia. However, the mechanism by which mulberry leaf and its functional components mediate atherosclerosis remains unclear. This study aimed to determine the effect of mulberry leaf extract (MLE) and its major component, neochlorogenic acid (nCGA), on the proliferation and migration of rat aortic vascular smooth muscle cells (VSMCs, A7r5 cell line) under diabetic cultured conditions (oleic acid and high glucose, OH). Our findings showed that MLE and nCGA significantly inhibited cell proliferation and migration in A7r5 cells as determined by a scratch wound assay and a Transwell assay. Furthermore, we observed MLE and nCGA inhibited cell proliferation and migration, such as reducing the phosphoinositide 3-kinases (PI3K)/protein kinase B (Akt), focal adhesion kinase (FAK), and small GTPase proteins using Western blot analysis. In conclusion, we confirmed the anti-atherosclerotic effects of MLE and nCGA in reducing vascular smooth muscle cell (VSMC) migration and proliferation under diabetic cultured conditions via inhibition of FAK/small GTPase proteins, PI3K/Akt, and Ras-related signaling.     

Formononetin Induces Apoptosis in PC-3 Prostate Cancer Cells Through Enhancing the Bax/Bcl-2 Ratios and Regulating the p38/Akt Pathway

Formononetin (FN), a bioactive component extracted from the red clover (Trifolium pratense L.), has been long used for treating carcinomas in China. In the present study, we aim to investigate the potential therapeutical effects of FN on cell line of prostatic adenocarcinoma (PC-3) and human prostate epithelial cells (RWPE1). These findings indicated that FN significantly inhibited the cell growth of PC-3 in a dose-dependent manner, but no such effect was observed in RWPE1 cells. The apoptotic counts were effectively increased following the treatments as shown in flow cytometry. The results from Western blotting assay suggested that FN treatment contributed to the reduced Bcl-2 protein level and the elevated Bax expression in PC-3 cells, thereby resulting in the increasing Bax/Bcl-2 ratios. Furthermore, the phosphorylated level of p38 in PC-3 cells was activated through the FN treatment, whereas the endogenous Akt phosphorylation was blocked. Collectively, our findings demonstrate that FN exerts the anticarcinogenic effect on prostate cancer in vitro, in which the underlying mechanisms are associated with enhancing the Bax/Bcl-2 ratios and regulating the p38/Akt pathway, thus triggering apoptosis in tumor cells.     

HPV16相关宫颈癌中PI3K/Akt自噬通路与HIF-1α的关系

几乎90%以上的宫颈癌都有高危人乳头瘤病毒（high risk human papilloma virus,HR-HPV）的持续感染,尤其当患者感染HPV16时,高级别宫颈上皮内瘤变或宫颈癌的发生风险可进一步上升。研究表明人类肿瘤中存在低氧现象,缺氧诱导因子1α（hypoxia-inducible factor-1α,HIF-1α）与低氧微环境关系最为密切,HIF-1α的活化能促进肿瘤生长,已成为目前的研究热点。经典的磷脂酰肌醇3激酶（phosphoinositide 3-kinase,PI3K）/蛋白激酶B（protein kinase B,Akt）自噬通路抑制自噬,并且在多种人类肿瘤中表达失调,其异常活化使细胞异常增殖、分化,促进肿瘤生长。综述HPV16感染可能引起HIF-1α与PI3K/Akt自噬通路变化的不同机制,探讨HPV16相关宫颈癌中PI3K/Akt自噬通路及HIF-1α的表达意义。     

Fruit Peel Polyphenolic Extract-Induced Apoptosis in Human Breast Cancer Cells Is Associated with ROS Production and Modulation of p38MAPK/Erk1/2 and the Akt Signaling Pathway

Polyphenols represent a large group of natural substances with different biological properties. Currently, polyphenols are well studied due to their free radicals' scavenging and antioxidant activities. However, some studies indicate that polyphenols also exhibit pro-oxidant properties. In this study, the possible involvement of the pro-oxidant activities of fruit polyphenols was investigated in relation to apoptosis induction. To determine the type of cell death induced by fruit polyphenols (Flavine; F7), we assessed a series of assays, including measurements of caspase-7 activation, membrane mitochondrial potential changes, reactive oxygen (ROS) and nitrogen species production, lipid peroxidation, antioxidant enzymes activities, and PARP cleavage. Moreover, the effect of F7 on selected pro- and antisurvival signaling pathways was determined. We demonstrated that fruit polyphenols induced caspase-dependent cell death associated with increased oxidative stress. We also showed fruit polyphenol-mediated release of mitochondrial pro- and antiapoptotic proteins of the Bcl-2 family and modulation activity of the Akt, p38 MAPK, and Erk 1/2 pathways as well as the signaling of ROS-mediated DNA damage. Our data demonstrated that fruit peel polyphenols suppressed breast cancer cell growth through increased intracellular oxidative stress and the activation of p38 MAPK and de-activation of the Erk 1/2 and Akt signaling pathways.     

砷对PI3K/AKT信号通路调节效应的Meta分析

目的系统评价砷(arsenic,As)对PI3K/AKT信号通路的多种调节效应,为揭示砷毒性作用机制提供理论依据。方法 2名研究者独立地评价中国知网、维普、万方、Cochrane、Embase、PubMed、Web of Science等数据库的文献质量,提取资料并进行交叉核对。对纳入的研究结果采用RevMan 5. 3和Stata 12. 0进行Meta分析。结果在体外实验中,与对照组相比,砷干预组PI3K、P-AKT水平均低于对照组,PTEN水平高于对照组,差异有统计学意义(Z分别为3. 01、3. 15和1. 97,P<0. 05);亚组分析发现,长时间(>24 h)砷干预组PTEN水平高于对照组,PI3K和P-AKT(ser473)水平均低于对照组,短时间(≤24 h)砷干预组P-AKT水平低于对照组,差异有统计学意义(Z分别为2. 06、2. 34、2. 92和2. 79,P<0. 05)。高浓度(≥3μmol/L)砷干预组PI3K及P-AKT水平均低于对照组,差异有统计学意义(Z分别为2. 46和3. 34,P<0. 05)。砷与PI3K抑制剂联合处理后的AKT、P-AKT及P-AKT(ser473)的表达比砷干预组下降更为明显。在体内实验中,砷干预组PI3K、P-AKT水平均低于对照组,差异有统计学意义(Z分别为2. 40、4. 25,P<0. 05);亚组分析可见,长时间(>14 d)砷干预组P-AKT水平,短时间(≤14 d)砷干预组PI3K、P-AKT、AKT水平均低于对照组,差异有统计学意义(Z分别为3. 01、4. 04、3. 67和2. 17,P<0. 05)。高浓度(>3 mg/kg)砷干预组PI3K、P-AKT,低浓度(≤3 mg/kg)砷干预组AKT、P-AKT水平均低于对照组,差异有统计学意义(Z分别为4. 04、3. 00、4. 33和2. 35,P<0. 05)。凋亡指标分析显示,砷干预后,凋亡相关蛋白Bax、Cytochrome C、Caspase3、Caspase9、PARP和Apoptosis rate表达水平较对照组均增加,差异有统计学意义(Z分别为3. 34、2. 47、2. 05、2. 36、2. 21和3. 16,P<0. 05),Bcl-2蛋白表达水平与对照组相比下降(Z=2. 05,P<0. 05)。结论砷可以通过抑制PI3K/AKT信号通路诱导细胞的调亡,其作用受到剂量、作用时间的影响。     

Sporoderm-Broken Spores of Ganoderma lucidum Inhibit the Growth of Lung Cancer: Involvement of the Akt/mTOR Signaling Pathway

The sporoderm-broken spores of Ganoderma lucidum (SBGS) and their extracts exhibited a wide range of biological activities. In the present study, we prepare ethanol/ethanol extract (E/E-SBGS) and ethanol/aqueous extract (E/A-SBGS) from SBGS and examine their antitumor activities against human lung cancer. Our results showed that E/E-SBGS, not E/A-SBGS, inhibited the survival and migration of lung cancer cells in a dose-dependent manner. E/E-SBGS arrested cell cycle at G2/M phase and triggered apoptosis by decreasing the expression and activity of cell cycle regulators, cyclin B1 and cdc2, as well as anti-apoptotic proteins, Bcl-2 and Bcl-xl. Consequently, colony formation of lung cancer cells was markedly blocked by E/E-SBGS at subtoxic concentrations. Oral administration of both E/E-SBGS and SBGS significantly suppressed tumor volume and tumor weight without gross toxicity in mice. Mechanism study showed that E/E-SBGS dose-dependently suppressed the activation of Akt, the mammalian target of rapamycin (mTOR) and their downstream molecules S6 kinase and 4E-BP1 in treated tumor cells. Taken together, these results indicate that the ethanol extract of sporoderm-broken spores of G. lucidum suppresses the growth of human lung cancer, at least in part, through inhibition of the Akt/mTOR signaling pathway, suggesting its potential role in cancer treatments.     

2,4-bis (p-hydroxyphenyl)-2-butenal (HPB242) Induces Apoptosis via Modulating E7 Expression and Inhibition of PI3K/Akt Pathway in SiHa Human Cervical Cancer Cells

The Maillard reaction is a chemical reaction occurring between an amino acid and a reducing sugar, usually requiring thermal processing. Maillard reaction products (MRPs) have antioxidant, antimutagenic, and antibacterial effects, and although 2,4-bis (p-hydroxyphenyl)-2-butenal (HPB242), a fructose-tyrosine MRP, appears to inhibit proliferation of cancer cells, its mechanism of action has not been studied in detail. We found that HPB242 treatment modulated expression of cyclins and tumor suppressor genes in SiHa human cervical cancer cell lines: cyclins and phospho-pRB were downregulated, whereas the expression of CDK inhibitors and p53 was enhanced. HPB242 induced apoptosis dose-dependently by suppressing E7 expression and leading to sub-G1 cell-cycle arrest in SiHa cell lines; treatment also led to the proteolytic cleavage of caspase-3, -9, and poly (ADP-ribose) polymerase. Moreover, HPB242 upregulated Fas expression, altered expressions of pro- and antiapoptotic factors, and also inhibited nuclear translocation of nuclear factor κB and phosphorylation of IκB. HPB242 treatment decreased phosphatidyl inositol-3 kinase and p-Akt expression levels, demonstrating that this survival pathway may also be inhibited by HPB242. Cumulatively, HPB242 promotes apoptosis by influencing E7 expression, inducing cell-cycle arrest at sub-G1 phase, and promoting both intrinsic (mitochondrial) and extrinsic (Fas-dependent) apoptosis in SiHa human cervical cancer cells.     

PI3K/AKT/Bcl-2通路在吡格列酮保护缺血再灌注损伤心肌细胞中作用的研究

目的 研究吡格列酮对缺血再灌注损伤心肌细胞的保护作用机制中PI3K/AKT/Bcl-2信号通路的作用.方法 取Wistar大鼠乳鼠心室肌细胞进行体外培养,缺氧、复氧各3 h后建立缺血再灌注损伤细胞模型.采用免疫细胞化学染色法检测细胞内Bcl-2蛋白含量,采用Western-bloting检测细胞内Bcl-2蛋白表达水平.结果 免疫细胞化学染色法及Western-bloting结果均显示：与Ⅰ组比较,P组Bcl-2表达明显增加（P〈0.05）;与P组比较,P＋Ly组Bcl-2表达明显减少（P〈0.05）.结论 吡格列酮减轻心肌缺血再灌注损伤保护机制与其激活PI3K/AKT/ Bcl-2信号通路有关.     

Endothelium-Dependent Relaxation Effect of Apocynum venetum Leaf Extract via Src/PI3K/Akt Signalling Pathway

Botanical herbs are consumed globally not only as an essential diet but also as medicines or as functional/recreational food supplements. The extract of the Apocynum venetum leaves (AVLE), also known as Luobuma, exerts its antihypertensive effect via dilating the blood vessels in an endothelium- and concentration-dependent manner with optimal effect seen at as low as 10 µg/mL. A commercial Luoboma “antihypertensive tea” is available commercially in the western province of China. The present study seeks to investigate the underlying cellular mechanisms of the nitric oxide (NO)-releasing property of AVLE in rat aortas and human umbilical vein endothelial cells (HUVECs). Endothelium-dependent relaxation induced by AVLE was assessed in organ chambers in the presence or absence of polyethyleneglycol catalase (PP2, 20 µM; inhibitor of Src kinase), wortmannin (30 nM) and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 (20 µM; PI3 (phosphatidylinositol3)-Kinase inhibitor), N^G-nitro-l-arginine (L-NAME, 100 µM; endothelial NO synthase inhibitor (eNOS)) and ODQ (1 µM; soluble guanylyl cyclase inhibitor). Total nitrite and nitrate (NOx) level and protein expression of p-Akt and p-eNOS were measured. AVLE-induced endothelium-dependent relaxation was reduced by PP2, wortmannin and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 and abolished by L-NAME and ODQ. AVLE significantly increased total NO_x level in rat aortas and in HUVECs compared to control. It also instigated phosphorylation of Akt and eNOS in cultured HUVECs in a concentration-dependent manner and this was markedly suppressed by PP2, wortmannin and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002. AVLE also inhibited superoxide generated from both NADPH oxidase and xanthine/xanthine oxidase system. Taken together, AVLE causes endothelium-dependent NO mediated relaxations of rat aortas through Src/PI3K/Akt dependent NO signalling pathway and possesses superoxide scavenging activity.