妊娠期糖尿病孕妇胎盘组织Akt和GLUT-1的表达与新生儿体重的相关性

目的探讨妊娠期糖尿病(GDM)孕妇胎盘组织Akt和GLUT-1的表达与新生儿体重的相关性。方法选取我院收治的40例GDM患者作为研究组,另选取40例健康孕妇作为对照组,检测两组孕妇的孕期BMI、孕期增重、 FPG、 FINS、HbA1c水平,分析胎盘组织Akt和GLUT-1表达情况及其与新生儿体重的相关性。结果研究组胎盘组织Akt和GLUT-1表达明显低于对照组(P <0.05)。Pearson相关性分析显示,Akt表达(r=-0.697, P=0.035)、 GLUT-1表达(r=-0.768, P=0.029)均与新生儿体重呈负相关。结论 GDM孕妇胎盘组织中Akt和GLUT-1表达水平下降可能是造成新生儿体重上升的原因。     

The anti-fibrotic effects of epigallocatechin-3-gallate in bile duct-ligated cholestatic rats and human hepatic stellate LX-2 cells are mediated by the PI3K/Akt/Smad pathway

Aim:

(−)-Epigallocatechin-3-gallate (EGCG) is one of the most abundant polyphenols in green tea with strong antioxidant activity and various therapeutic effects. In this study, we investigated the anti-fibrotic effects of EGCG and underlying mechanisms in bile duct-ligated (BDL) rats and a liver fibrosis model in vitro.

Methods:

BDL rats were treated with EGCG (25 mg·kg⁻¹·d⁻¹, po) for 14 d, and then the serum, bile and liver samples were collected. Liver fibrosis was assessed by serum, urine and bile biochemistry analyses and morphological studies of liver tissues. TGF-β1-stimulated human hepatic stellate LX-2 cells were used as a liver fibrosis model in vitro. The expression of liver fibrogenic genes and signaling proteins in the PI3K/Akt/Smad pathway was examined using Western blotting and/or real-time PCR.

Results:

In BDL rats, EGCG treatment significantly ameliorates liver necrosis, inflammation and fibrosis, and suppressed expression of the genes associated with liver inflammation and fibrogenesis, including TNF-α, IL-1β, TGF-β1, MMP-9, α-SMA, and COL1A1. In LX-2 cells, application of EGCG (10, 25 μmol/L) dose-dependently suppressed TGF-β1-stimulated expression of COL1A1, MMP-2, MMP-9, TGF-β1, TIMP1, and α-SMA. Furthermore, EGCG significantly suppressed the phosphorylation of Smad2/3 and Akt in the livers of BDL rats and in TGF-β1-stimulated LX-2 cells. Application of {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002, a specific inhibitor of PI3K, produced similar effects as EGCG did in TGF-β1-stimulated LX-2 cells, but co-application of EGCG and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 did not produce additive effects.

Conclusion:

EGCG exerts anti-fibrotic effects in BDL rats and TGF-β1-stimulated LX-2 cells in vitro via inhibiting the PI3K/Akt/Smad pathway.     

桔皮素对人非小细胞肺癌细胞生长及侵袭的影响

目的:探讨桔皮素(TGN)对非小细胞肺癌(NSCLC)细胞生长和侵袭的影响及其分子机制。方法:体外培养非小细胞肺癌A549细胞,分别用不同浓度的TGN处理,MTT比色法检测细胞活性,Annexin V-FITC/PI染色及流式细胞术检测细胞凋亡率,Transwell检测细胞侵袭,RT-PCR分析MMP-2和MMP-9的mRNA表达水平,Western blotting检测Ki67、Cyt C、caspase-3、cleaved caspase-3、MMP-2、MMP-9、Akt、p-Akt以及p-PI3K表达水平。结果:桔皮素剂量依赖性地抑制A549细胞增殖(P0.05),同时伴随有增殖标记分子Ki67表达水平的下调。分析发现,桔皮素诱导细胞中Cyt C、caspase-3和cleaved caspase-3的表达上调(P0.01),加速A549细胞的凋亡。此外,桔皮素作用后,A549细胞中侵袭相关蛋白MMP-2和MMP-9的表达量下降,且侵袭数目随桔皮素浓度增加而减少。进一步研究表明,桔皮素作用后A549细胞中p-Akt和p-PI3K表达水平降低(P0.05),阻断PI3K/Akt信号通路后,不同浓度TGN对细胞活性影响没有变化。结论:桔皮素能抑制A549细胞生长及侵袭,促进细胞凋亡,可能通过抑制PI3K/Akt信号通路的激活起作用。因此,本研究将为非小细胞肺癌的防治提供新的研究方向。     

PI3K/Akt信号通路在乳腺癌内分泌治疗耐药中的作用及对策

乳腺癌是女性最常见的肿瘤,大约75％的乳腺癌表达雌激素受体和/或孕激素受体.激素受体阳性的转移性乳腺癌患者通常采用内分泌治疗,然而由于内分泌治疗耐药的产生,其应用受到了限制.近年来发现,PI3K/Akt(丝氨酸/苏氨酸激酶)信号通路在乳腺癌的发展中发挥着重要作用.本文对PI3K/Akt信号通路在乳腺癌内分泌治疗耐药中的作用进行了综述,以期为雌激素受体阳性乳腺癌治疗提供新对策.     

高迁移率蛋白B1对血管平滑肌细胞迁移的影响及分子机制研究

目的：探讨高迁移率蛋白B1（HMGB1）对血管平滑肌细胞（VSMCs）迁移的影响及 TLR4依赖的 TLR4／PI3K／Akt信号通路介导的分子机制。方法体外分离培养大鼠胸主动脉VSMCs ,采用不同浓度 HMGB1（0．1～1000．0 ng ／mL）处理,分为对照组（未经任何处理）、HMGB1组、HMGB1＋ TLR4 siRNA转染组、Control siRNA转染组和磷脂酰肌醇3‐激酶（PI3K）抑制剂（LY294002）干预组,观察各组细胞活性及 HMGB1对 VSMCs 迁移的影响;实时定量 RT‐PCR与 Western blot 分别检测TLR4、Akt、p‐Akt、PI3K mRNA和蛋白的表达;ELISA测定PI3K的活性。结果 HMGB1（0．1～1000．0 ng／mL）呈剂量依赖性促进VSMCs迁移（P＜ 0．05）;经细胞活性测定,HMGB1在使用的浓度范围内对 VSMCs未造成细胞毒性作用（P＜ 0．05）;HMGB1（100 ng／mL）处理的 VSMCs细胞组 PI3K 活性及 Akt磷酸化水平明显增加（P＜ 0．05）;经 TLR4 siRNA 转染发现, HMGB1引起的VSMCs迁移明显减弱（P＜0．05）,同样在PI3k抑制剂干预组,PI3K／Akt途径活化和HMGB1介导的VSMCs迁移也被明显抑制（P＜0．05）。结论 HMGB1呈剂量依赖性促进VSMCs迁移,TLR4依赖的 TLR4／PI3K／Akt信号通路参与了此过程,提示以TLR4依赖的PI3K／Akt途径为靶点,可为阻塞性血管疾病的治疗提供新思路。     

Molecular mechanisms of human thyrocyte dysfunction induced by low concentrations of polychlorinated biphenyl 118 through the Akt/FoxO3a/NIS pathway

Polychlorinated biphenyls (PCBs) are typical persistent organic pollutants that can interfere with multiple organ systems of humans. Previously, we concluded that persistent exposure to low doses of PCB118 could severely damage the thyroidal structure, dramatically decrease the concentration of serum thyroid hormones and inhibit the pivotal gene expressions such as sodium/iodide symporter (NIS) and thyroglobulin (Tg). To explore the molecular mechanisms of thyrocyte dysfunction induced by 2,3′,4,4′,5‐pentachlorobiphenyl (PCB118), monolayer cultured human thyroid epithelial cells (HTECs) were treated with PCB118 or dimethyl sulfoxide (DMSO) as a control. Our results indicated that relatively higher concentrations of PCB118 could induce a loss in the viability of HTEC. In cultures with concentrations of PCB118 from 0.025 to 25 nM, which did not affect cell viability or apoptosis, concentrations of Tg and thyroxine (T₄) were significantly decreased compared with those in the controls. In addition, mRNA and protein levels of Akt were increased significantly in the PCB118‐treated groups, whereas FoxO3a expression did not show particular variation. Furthermore, exposure to PCB118 was associated with a significant increase of the protein levels of p‐Akt and p‐FoxO3a, and these effects were blocked by LY294002. In contrast, mRNA and protein expression levels of NIS were decreased significantly, and this effect was blocked by LY294002. Unlike control cells, a cytoplasmic shift of FoxO3a was observed in the PCB118‐treated group. Our research suggests that PCB118 may induce thyrocyte dysfunction through the Akt/FoxO3a/NIS signalling pathway, which provides potential new insights for finding interventions to counteract the damage to the human body caused by PCBs. Copyright © 2015 John Wiley & Sons, Ltd.     

Carnosic acid induces autophagic cell death through inhibition of the Akt/mTOR pathway in human hepatoma cells

The therapeutic goal of cancer treatment is now geared towards triggering tumour‐selective cell death with autophagic cell death being required for the chemotherapy of apoptosis‐resistant cancer. In this study, Carnosic acid (CA), a polyphenolic diterpene isolated from Rosemary (Rosemarinus officinalis), significantly induced autophagic cell death in HepG2 cells. Ca treatment caused the formation of autophagic vacuoles produced an increasing ratio of LC3‐II to LC3‐I in a time‐ and dose‐dependent manner but had no effect on the levels of autophagy‐related protein ATG6 and ATG13 expression. Autophagy inhibitors, 3‐methyladenine (3‐MA), chloroquine and bafilomycin A1, or ATG genes silencing in HepG2 cells significantly inhibited CA‐induced autophagic cell death. The CA treatment decreased the levels of phosphorylated Akt and mTOR without any effects on PI3K or PTEN. Most importantly, overexpression of Akt and knockdown of PTEN attenuated autophagy induction in CA‐treated cells. Taken together, our results indicated that CA induced autophagic cell death through inhibition of the Akt/mTOR pathway in human hepatoma cells. These findings suggest that CA has a great potential for the treatment of hepatoma via autophagic induction. Copyright © 2014 John Wiley & Sons, Ltd.