津力达对胰岛素抵抗大鼠肝脏PI3K/AKT信号通路的影响

目的:探讨津力达改善大鼠胰岛素敏感性的分子作用机制。方法:48只SD大鼠随机分为正常组和高脂饮食组,分别予以普通饲料及高脂饲料喂养。喂养后6周后行高胰岛素-正葡萄糖钳夹实验,鉴定胰岛素抵抗大鼠造模成功。随后将高脂喂养组分为5组,分别为模型组、津力达低、中、高剂量组(0.75,1.5,3.0 g·kg-1)和二甲双胍组(0.2 g·kg-1)。药物干预8周后行钳夹实验和ip葡萄糖耐量实验,并留取大鼠血清,测定空腹血糖(FBG),空腹胰岛素(FINS),糖化血红蛋白(Hb A1c),葡萄糖输注率(GIR),甘油三酯(TG),总胆固醇(TC),高密度脂蛋白胆固醇(HDL-C),低密度脂蛋白胆固醇(LDLC),极低密度脂蛋白胆固醇(VLDL-C)水平;并留取大鼠肝脏标本,RT-PCR检测肝脏胰岛素受体(INSR),胰岛素受体底物-1(IRS-1),蛋白激酶B(AKT),磷脂酰肌醇3激酶(PI3K)和葡萄糖转运蛋白2(GLUT2)的mRNA表达水平,Western blot检测IRS-1和AKT的总蛋白及磷酸化蛋白表达水平,并计算p-AKT/AKT和p-IRS-1/IRS-1。结果:与正常组比较,模型组FBG,FINS,Hb A1c,TC及VLDL-C水平明显升高(P0.05),INSR,IRS-1,PI3K,AKT和GLUT2 mRNA表达下降,HDL-C,GIR含量明显降低(P0.05),p-IRS-1/IRS-1明显升高,p-AKT/AKT明显降低(P0.05);与模型组比较,津力达干预后,大鼠葡萄糖输注率明显升高,FBG,FINS,Hb A1c,TG,TC,LDL-C及VLDL-C水平明显降低(P0.05),对HDL-C无明显影响,津力达明显上调肝脏INS,IRS-1,AKT和GLUT2 mRNA表达(P0.05),升高GIR含量,对PI3K无显著影响;津力达干预组p-IRS-1/IRS-1明显降低,p-AKT/AKT明显升高(P0.05)。结论:津力达可改善胰岛素抵抗,纠正糖脂代谢紊乱,可能与上调PI3K/AKT信号通路有关。     

抗纤灵方通过PI3K/AKT/mTOR信号通路干预肾纤维化机制研究

目的:研究抗纤灵方对PI3K/AKT/mTOR信号通路的影响及抗肾纤维化作用机制。方法:将60只C57小鼠,随机分为假手术组10只和手术组50只,手术组行5/6肾切除术。术后2周,手术组随机分为模型组、抗纤灵低、中、高剂量组及雷帕霉素阳性药组,各组10只。假手术组给予0.5 mL生理盐水ig,抗纤灵方低、中、高剂量组分别给予0.5 mL抗纤灵药物ig(0.1,0.2,0.4 mg·kg-1),阳性药组给予0.5 mL雷帕霉素ig(0.016μg·kg-1),ig 12周后处死小鼠,在处死小鼠前1 d收集24 h尿液检测24 h蛋白定量,眼眶采血测血肌酐、尿素氮,取残肾采用HE观察肾脏组织形态改变,PCR法检测肾组织中PI3K/AKT/mTOR mRNA表达。结果:与假手术组比较,模型组24 h尿蛋白定量,血肌酐,尿素氮,PI3K/AKT/mTOR mRNA表达均显著升高(P0.01),肾脏病理形态改变明显;与模型组比较,各治疗组24 h尿蛋白定量,血肌酐,尿素氮,PI3K/AKT/mTOR mRNA表达均下降(P0.05),肾脏组织学形态改善。结论:抗纤灵方能降低小鼠24 h尿蛋白定量,改善肾功能,延缓肾纤维化发生;其机制可能与抑制PI3K/AKT/mTOR信号通路表达相关。     

丹蒌片通过PI3K/Akt信号通路抗动脉粥样硬化机制研究

目的：观察丹蒌片对动脉粥样硬化兔血脂、炎症因子及PI3K/AKT信号通路的影响,并探讨丹蒌片抗动脉粥样硬化的机制。方法：雄性日本大耳白兔24只,随机分为正常对照组、模型组、丹蒌片组,每组8只。正常对照组饲喂普通饲料,其余各组高脂饲料喂养制备动脉粥样硬化模型;除高脂饲料喂养外,丹蒌片组（0.5 g·kg^-1·d^-1）胃饲相应药物。连续给药9周后处死,测各组血脂、血清肿瘤坏死因子（TNF-α）和白介素-6（IL-6）的含量;HE染色观察主动脉病理学改变;Western blot检测主动脉中PI3K和p-AKT的蛋白表达水平。结果：与正常对照组比较,模型组中甘油三酯（TG）、总胆固醇（TC）和低密度脂蛋白（LDL）及IL-6、TNF-α的浓度均显著升高（P<0.01）,主动脉组织中PI3K、p-AKT的蛋白表达水平明显降低（P<0.01）。与模型组相比,丹蒌片组血脂及IL-6、TNF-α水平明显降低（P<0.05或P<0.01）,PI3K、p-AKT的蛋白表达显著升高（P<0.01）。结论：丹蒌片具有降低兔血脂、炎症因子,抗动脉粥样硬化的作用,其作用机制可能与激活PI3K/AKT信号通路相关。     

PTEN loss is a context‐dependent outcome determinant in obese and non‐obese endometrioid endometrial cancer patients

Endometrial cancer incidence is increasing, due in part to a strong association with obesity. Mutations in the phosphatidylinositol 3‐kinase (PI3K) pathway, the central relay pathway of insulin signals, occur in the majority of endometrioid adenocarcinomas, the most common form of endometrial cancer. We sought to determine the impact of PI3K pathway alterations on progression free survival in a cohort of endometrioid endometrial cancers. Prognostic utility of PIK3CA, PIK3R1, and PTEN mutations, as well as PTEN protein loss by immunohistochemistry, was explored in the context of patient body mass index. Reverse‐phase protein arrays were utilized to assess protein expression based on PTEN status. Among 187 endometrioid endometrial cancers, there were no statistically significant associations between PFS and PIK3CA, PIK3R1, PTEN mutation or loss. When stratified by body mass index, PTEN loss was associated with improved progression free survival (P < 0.006) in obese (body mass index ≥ 30) patients. PTEN loss resulted in distinct protein changes: Canonical PI3K pathway activation was observed only in the non‐obese population while decreased expression of β‐CATENIN and phosphorylated FOXO3A was observed in obese patients. These data suggest the impact of PTEN loss on tumor biology and clinical outcomes must be interpreted in the context of body mass index, and provide a potential explanation for discrepant reports on the effect of PTEN status and obesity on prognosis in endometrial cancer. This reveals a clinically important interaction between metabolic state and tumor genetics that may unveil the biologic underpinning of obesity‐related cancers and impact ongoing clinical trials with PI3K pathway inhibitors.     

Function of phosphorylation of NF-kB p65 ser536 in prostate cancer oncogenesis

Majority of prostate cancer (PCa) patients carry TMPRSS2/ERG (T/E) fusion genes and there has been tremendous interest in understanding how the T/E fusion may promote progression of PCa. We showed that T/E fusion can activate NF-kB pathway by increasing phosphorylation of NF-kB p65 Ser536 (p536), but the function of p536 has never been studied in PCa. We report here that active p536 can significantly increase cell motility and transform PNT1a cells (an immortalized normal cell line), suggesting p536 plays a critical role in promoting PCa tumorigenesis. We have discovered a set of p536 regulated genes, among which we validated the regulation of CCL2 by p536. Based on all evidence, we favor that T/E fusion, NF-kB p536 and CCL2 form a signaling chain. Finally, PNT1a cells (not tumorigenic) can form tumors in SCID mice when overexpressing of either wild type or active p65 in the presence of activated AKT, demonstrating synergistic activities of NF-kB and AKT signals in promoting PCa tumorigenesis. These findings indicate that combination therapies targeting T/E fusion, NF-kB, CCL2 and/or AKT pathways may have efficacy in T/E fusion gene expressing PCa. If successful, such targeted therapy will benefit more than half of PCa patients who carry T/E fusions.     

MicroRNA-3127 promotes cell proliferation and tumorigenicity in hepatocellular carcinoma by disrupting of PI3K/AKT negative regulation

Recent studies have shown that multiple phosphatases deactivate the PI3K/AKT signaling pathway. Here we demonstrated that, by suppressing multiple phosphatases, miR-3127 promotes growth of hepatocellular carcinoma (HCC). Our study also reveals clinical significance of miR-3127 expression in HCC patients. MiR-3127 expression was markedly upregulated in HCC tissues and cells. Furthermore, high miR-3127 expression was associated with an aggressive phenotype and poor prognosis. MiR-3127 overexpression promoted HCC cell proliferation in vitro and tumor growth in vivo. Also, miR-3127 accelerated G1-S transition by activating AKT/FOXO1 signaling, by directly targeting the 3′ untranslated regions (3`UTR) of pleckstrin homology domain leucine-rich repeat protein phosphatase 1/2 (PHLPP1/2), inositol polyphosphate phosphatase 4A (INPP4A), and inositol polyphosphate-5-phosphatase J (INPP5J) mRNA, repressing their expression. In agreement, the miRNA antagonist antagomir-3127 suppressed HCC cell proliferation and tumor growth by inhibiting the AKT/FOXO1 signaling. Taken together, these findings suggest that silencing miR-3127 might be a potential therapeutic strategy.     

Confirmation of genetic variants associated with lethal prostate cancer in a cohort of men from hereditary prostate cancer families

Germline genetic variants have been suggested as prognostic biomarkers for identifying patients at high risk for lethal prostate cancer (PCa). Validation studies have confirmed the association of several single nucleotide polymorphisms (SNPs) with fatal PCa, but whether these variants affect PCa‐specific mortality (PCSM) in patients with an inherited predisposition to PCa, based on familial history, is unknown. For this study, a cohort of 957 PCa patients from 270 hereditary prostate cancer families of European ancestry was genotyped for a panel of 22 PCSM‐associated SNPs. Death certificates were reviewed to confirm cause of death. Mixed‐effect Cox proportional hazards models were used to assess survival according to genotypes, accounting for relatedness and clinicopathological factors. Within this cohort, 98 PCa deaths were confirmed over an average follow‐up period of 12.7 years after diagnosis. Variant allele carriers for three SNPs had significantly altered risk for PCSM [rs635261 at RNASEL, hazard ratio (HR), 0.35, 95% CI, 0.18–0.66; p = 0.002; rs915927 in XRCC1, HR, 1.91, 95% CI, 1.21–3.02; p = 0.009; and rs2494750 at AKT1, HR, 0.45, 95% CI, 0.23–0.90; p = 0.016). These results confirm the association of genetic variation in three genes with PCa lethality in a cohort of men with an inherited susceptibility to the disease and provide validation evidence that germline SNPs provide prognostic information for PCa patients. Development of a panel of germline biomarkers with clinical utility for distinguishing patients at detection who have an increased risk for fatal PCa is warranted.